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KLYN C
CONTRAC

BOARD OF WATER SUPPLY

THE CITY OF NEW YORK

CATSKILL WATER SUPPLY

Reports, Letters, Resolutions and Authorizations

ON THE

CITY TUNNEL AND THE DELIVERY OF
CATSKILL WATER

TO THE

SEVERAL BOROUGHS OF THE CITY

New York Cfty
J9J2

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182239 ^

FG 27 1914

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•N4£

TABLE OF CONTENTS

PAGE

Introductory 1

History of City tunnel 3

Report of Department Engineer to Chief Engineer 9

General conditions governing delivery of Catskill water 11

Location of delivery conduits 12

Size of conduits 14

Possible types of conduit construction 14

Economic size of pressure tunnel 16

Effect on system for Brooklyn and Richmond as outlined Oct. 9, 1905. 18

Type of conduit suitable for various boroughs 19

The Bronx 19

Manhattan 19

Brooklyn 19

Queens 20

Richmond fc 20

Equalizing reservoirs 20

Time required for construction 21

Estimated cost 22

Combined tunnel and pipe-line 22

Pipe-line system 23

Report of Chief Engineer to Board of Water Supply 25

Concurrence of Consulting Engineers 27

Transmittal of plan to Board of Estimate and Apportionment 29

Notice of public hearing on plan 30

Appointment of committee to report on plan 31

Opinion of Chief Engineer, Dept. of W. S., G. & E 32

Opinion of Chief Engineer, Dept. of W. S. f G. & E., Brooklyn 33

Report of majority of committee on plan 35

Report of minority of committee on plan 41

Approval of plan by Board of Estimate and Apportionment 43

Transmittal of petition to State Water Supply Commission 45

Petition to State Water Supply Commission 47

Affidavit of City Clerk 54

Public notice by State Water Supply Commission 55

Resolutions adopted by Board of Estimate and Apportionment 57

State Water Supply Commission to defer action 57

Committee to investigate pressure tunnel plan 59

Report of experts on pressure tunnel 60

Practicability — Manhattan pressure tunnel 60

Borings, making and completed 61

Available data 61

Geological conclusions 62

Other pressure tunnels in the United States 62

Opinion on proposed tunnel 64

Comparative projects , 65

Increased pressure when desired 65

Pumping to be dispensed with 66

Brooklyn pumping wholly to be dispensed with for a time 66

Consumption of Catskill water in Manhattan 67

J7 CONTENTS

PAGE

Cross-connection, Manhattan-Brooklyn 67

Parallel lines of water mains 68

First cost comparisons 68

Route comparison 69

Question 3 — Better route for pressure tunnel 70

Conclusion 70

Cost estimate 70

Estimated time of completion 71

Other distribution plans considered 71

Building at intervals 71

Pipe galleries 71

Water waste prevention . . . 72

Appendix A — Geological problems involved 74

Rocks traversed by proposed line 74

General description of rocks along tunnel line 74

Proportions of different rocks encountered. . . . 76

Dangers to pressure tunnels due to rock condition 76

Location of pressure tunnels 80

Exploration of rock 81

Opinion on practicability of tunnel 82

Appendix B — Results of rock borings along tunnel line 84

Appendix C — Geology of Lower East Side. 86

Details of holes 87

Microscopic examination of rock cores 88

Summary of interpretation 88

Opinion on construction of tunnel at depth proposed 89

Appendix D — Pressure tunnel to deliver 500 M. G. D 90

History of plan 90

Estimated length and size of tunnel and pipe-lines 92

Estimated cost of pressure tunnels 93

Estimated cost of pipe-line extensions 93

Estimated cost of distribution reservoir 93

Appendix E — Pipe-line to deliver 500 M. G. D 94

Estimated cost 95

Appendix F — Detailed costs 96

Estimated prices for pressure tunnels 96

Estimated cost for shaft sinking 96

Estimated cost for pipes 97

Appendix G — Progress reports on similar work. Time for completion. 98

Shaft progress on Catskill Aqueduct works 98

New York subway 98

Tunnel progress 98

Progress assumed for this report 98

Time for completion of controlling sections 99

Appendix H — Comparative cost of tunnels 100

To deliver 500 M. G. D 100

To deliver 250 M. G. D 100

Appendix I — Pipe-line to deliver 250 M. G. D 101

Report of committee of Board of Estimate and Apportionment 103

Approval of plan by Board of Estimate and Apportionment 107

Decision of State Water Supply Commission 109

Certification of copy of decision 113

Canvasses of bids of Contracts 63, 65, 66, 67, 75, 87 and 103 114

Report of Charles P. Berkey 115

Geological features of City distribution tunnel 115

Preliminary studies 115

General considerations 116

Questions of distribution conduit trial lines 116

C0NTENT8 III

PAGE

Geological studies 117

Geological formations 118

The glacial drift 118

Manhattan schist 119

Inwood limestone 120

Fordham gneiss 121

Yonkers gneiss 123

Ravenswood grano-diorite 123

Structural features 124

Folds 124

Faults 126

Unconformities 127

Physiographic history 127

Geologic map 131

Special comparative study of trial lines •••••.• 131

Line A — Southward from Hill View reservoir 132

Summary of Line A 132

Line B — Southward from Hill View reservoir 133

Summary of Line B 133

Line C — Southward from Hill View reservoir 133

Summary of Line C 134

Tabulated summary — Types of rock formation 135

Summary of quality 135

Argument on choice of line 135

Depth of tunnel 137

Effect on construction if lines are shifted 137

Advisable changes in lines 138

Recommendations of Lines F, G, H and 1 138

Line F — (Westerly) beginning at Hill View reservoir 139

Line G 139

Line H 139

Line 1 140

Tabulation — Estimated length of rock types 140

Comparative summary of types of formation 140

Estimated summary of quality 141

General conclusions 142

Revised lines 142

Points for exploration north of 59th street 143

Special study of conditions south of 59th street 143

East River area 145

Manhattan side 145

Special exploration zones 147

Harlem River crossing 148

Hole 17— Near High bridge 150

Summary 152

Interpretation 152

Hole 42— Near High bridge •. . . 153

Geologic cross-section 155

Manhattanville cross valley 155

General geologic conditions established 157

Morningside to Central park 157

Hole 7 — Manhattan avenue and 113th street 159

Hole 16 — Manhattan avenue and 110th street 160

Hole 36 — Manhattan avenue and 108th street 161

Hole 2 — 123rd street 100 feet east of Morningside park. . 161

Hole 33 — 121st street 300 feet east of Morningside park. . 162

Limestone-schist contact along Morningside section 162

Depth of decay at south end of Morningside park 163

IV CONTENTS

PAGE

East River section ' 166

Geology of Delancey and Clinton Street section 168

Borings 169

Fault zones 170

Interbedded limestones in Fordham series 171

Character of drift cover of Lower East Side section 174

. Wash borings from Hole 225 174

Comment on materials 177

Conditions at proposed Silver Lake reservoir 178

Questions on geology of site 178

Geological formations 178

Imperviousness of the basins 180

Material for dike construction 182

Explorations 182

Summary 183

Question of feasibility of tunnel plan 1§3

ILLUSTRATIONS

PAGE

Catskill aqueduct. City tunnel and pipe lines — Sheet 1 Frontispiece

Harlem River crossing. Hole 42, 455 feet deep, which penetrated con-
tact between limestone and schist, and furnished cores which were
1% inches to 3 inches in diameter; 97 per cent, of the limestone
core was recovered. Contract 38. October 13, 1909 — Plate 1 12

Shot drill at southwest corner of 123rd street and Morningside avenue
working under Contract 38. This drill penetrated 320 feet and fur-
nished 3-inch cores. October 13, 1909 — Plate 2 14

Shot drill furnishing 1%-inch core at 110th street and Morningside ave-
nue. Contract 38. October 13, 1909 — Plate 3 16

Closed box contains core recovered from Hole 42 at contact between lime-
stone and schist under Harlem river. Open boxes contain 3-inch,
1%-inch and 1-inch cores. November 12, 1909 — Plate 4 20

Catskill aqueduct. City tunnel and conduits. Tunnel and pipe lines

— Sheet 2 24

Catskill aqueduct. City conduits. Pipe lines — Sheet 3 24

East River crossing. Drill furnishing 1-inch core working on barge at
foot of Jay street, Brooklyn. Contract 38. August 12, 1909 —
Plate 5 26

Catskill aqueduct. Map and profile showing manner of delivering the

water to the several boroughs. November 15, 1909— Sheet 4 28

Graphic geologic study of the alternative lines for distribution conduits

—Sheet 5 142

Generalized geologic cross-section from the New Jersey side of Hudson

river at Hoboken to the Long Island side of East river at the ,
Brooklyn Navy Yard — Sheet 5 142

Revised areal geology of southern Manhattan Island and the adjacent

margin of Long Island — Sheet 6 144

Key map showing plan of exploratory borings at the Harlem River cross-
ing, location of the New Croton aqueduct which crosses the Harlem
in a pressure tunnel and the Old Croton aqueduct which crosses the
river on High bridge — Sheet 7 149

Harlem River crossing. New Croton Aqueduct — Sheet 8 154

Geologic section on the aqueduct line across the Harlem river about

167th street — Sheet 8 154

Geologic detail of the Manhattanville-Morningside section showing the
alternative lines studied, the locations of exploratory borings, the
two principal crush zones and longitudinal profiles — Sheet 9 158

Geologic cross-section of the Line A-B near 110th street, from Morning-
side Heights to Central park, showing the anticlinal structure and
location of the crush zone along which deep erosion and decay have
been found — Sheet 10 165

Profile of surface and rock floor as indicated by borings from the foot
of Clinton street, Manhattan, to Gold street and Myrtle avenue,
Brooklyn — Sheet 11 167

Catskill aqueduct. City tunnel. Boring record, foot of Clinton street to

Delancey street and the Bowery — Sheets 12, 13, 14 and 15 174-176

Silver Lake reservoir. Location plan. Borings — Sheet 16 179

Silver Lake reservoir. Borings. Profiles perpendicular to the South

dike— Sheet 17 , 182

Map showing geologic formations along the proposed lines for distribution

conduits — Sheet 18 End of book

INTRODUCTORY

The magnitude and importance of the work of the City
tunnel of the Catskill aqueduct are of such a nature and the
introduction of Catskill water will have so far-reaching an
effect in improving the water-supply of The City that it has
been deemed expedient, in order to make permanent and ren-
der readily accessible a history of the various steps and stages
in the procedure which was followed preliminary to the final
adoption of the plans for this tunnel, to gather into one volume
the principal reports, letters, resolutions and authorizations
which this procedure involved.

To the end that the various steps and movements neces-
sitated by these preliminary proceedings may be easily co-
ordinated and in proper sequence, their presentation is pre-
ceded by a brief account of the history of the case down to the
beginning of the work of construction.

Charles Strauss
Charles N. Chadwick
John F. Galvin

Commissioners, Board of Water Supply

April 15, 1912

THE CITY TUNNEL OF THE CATSKILL WATER

SUPPLY AND THE DELIVERY OF WATER TO

THE SEVERAL BOROUGHS OF THE CITY

Under the authority of Chapter 724 of the Laws of 1905
as from time to time amended, the Board of Water Supply
has, since the date of its creation in June, 1905, proceeded
with the various questions involved in the obtaining and de-
livering to the City of a supply of pure and wholesome water.

On October 9, 1905, the Board of Water Supply presented
to the Board of Estimate and Apportionment a report covering
a plan for obtaining a supply of not less than 500,000,000 gal-
lons per day from the watersheds of the Esopus, Schoharie,
Rondout and Catskill creeks, said watersheds being situated
almost wholly in the counties of Ulster, Greene and Schoharie.
This plan provided for the delivery of the stated quantity of
water into the Hill View reservoir, located in the City of
Yonkers about J4 mile north of the limits of The City of New
York. This original plan of October 9, 1905 provided, how-
ever, only for the delivery of 120,000,000 gallons per day to
the Boroughs of Brooklyn and Richmond. The report accom-
panying this plan stated that " The main distributing lines
from the Hill View reservoir to the Boroughs of Manhattan,
Queens and The Bronx, are matters for later consideration."

The general plan above referred to was, by resolution, ap-
proved by the Board of Estimate and Apportionment on Octo-
ber 27, 1905, and thereafter, pursuant to statute, application
was made to the State Water Supply Commission for approval.
With certain minor modifications, the State Water Supply
Commission handed down its approval on May 14, 1906.

The Board- of Water Supply having in mind the necessity
for providing a comprehensive plan for the delivery of the
Catskill water to each of the several boroughs of The City,
thereafter continued its studies of this question. Two gen-
eral plans for attaining the desired result presented them-
selves : First, the use of metal pipes laid in the usual manner
through the City streets; second, a tunnel deep in the rock
from which connections would be made to the distribution
system through the shafts which of necessity would be re-
quired in its construction. To use metal pipes for the delivery

of this water would have required as many as 16 pipes, each
66 inches in diameter, and would have resulted in crowding
many streets already badly encumbered with subsurface struc-
tures, pipes and conduits of various kinds. Such pipes might
even interfere with future subway development along the
main avenues of Manhattan.

The plan for a pressure tunnel deep in the rock and far
below the level in the streets generally used for subsurface
structures presented many advantages and, after comprehen-
sive investigations and borings had been made, it was shown
to be perfectly feasible. The principal results of the borings
and geological investigations are set forth in a report by the
geological expert (see page 115). This report has been revised
and includes all information to date.

Among the various advantages possessed by the deep tun-
nel there may be briefly mentioned the following:

( 1 ) Smaller first cost.

(2) Smaller annual charges for sinking fund, depreciation
charges, repairs and maintenance.

(3) Non-interference with street surface structures dur-
ing construction and use of the subsurface for subways, sewers
and other structures.

(4) A minimum of depreciation and therefore a minimum
of repairs with their resultant interference with the surface of
the streets.

(5) Interference with service because of breaks reduced
to a minimum.

(6) Practically no disturbance to streets during construc-
tion.

(7) The possibility of delivering at any point along the
line of the tunnel a quantity of water greater than could be
delivered by any other means, this feature having particular
relation to the requirements during a great fire.

(8) Adequate cross-connection of all present distribution
systems so that the main supply of any system could be tem-
porarily put out of service and its territory supplied through
the feeders of other systems.

As the result of the studies and investigations, the depart-
ment engineer in immediate charge of these investigations in
his report of October 1, 1909, to the Chief Engineer, sum-

marized his conclusions substantially as above and estimated
the cost, including the reservoir in Richmond, at $24,650,000.
(See page 22.)

The Chief Engineer of the Board of Water Supply on No-
vember 1, 1909, recommended to the Board the adoption of
the deep tunnel plan, stating among other reasons that this
type of construction would be the most permanent, that it
would deliver the water under a greater head and that its
execution would result in a minimum of interference with both
present and future subsurface structures and public travel.
(See page 25.) This report of the Chief Engineer was con-
curred in by the three consulting engineers of the Board.

The Board of Water Supply under date of November 15,
1909, addressed a communication to the Board of Estimate
and Apportionment, submitting the plan for a pressure tunnel
from the Hill View reservoir, beneath the Boroughs of The
Bronx and Manhattan, to the Borough of Brooklyn, with
lines of metal pipes to the Boroughs of Queens and Rich-
mond. (See page 29.) The Board of Estimate and Appor-
tionment, by resolution, then appointed December 3, 1909,
as a date for a public hearing on this plan. (See page 30.)
At this public hearing the Board of Estimate and Apportion-
ment appointed a committee consisting of an engineer to be
designated by the Board of Water Supply, the Chief Engineer
of the Board of Estimate and Apportionment, the Chief En-
gineer of the Department of Finance, and the Hon. Lir.don
Bates, Jr., said committee being instructed to consider the
proposed plan for the pressure tunnel and to report back to
the Board at its meeting of December 10, 1909. (See page 31.)

Under dates of December 6 and December 8, 1909, the
Chief Engineer of the Department of Water Supply, Gas and
Electricity, and the Chief Engineer of that department for the
Borough of Brooklyn, addressed letters to the Chief Engineer
of the Board of Water Supply and favored the pressure tun-
nel plan for the delivery of the Catskill water. (See pages
32 and 33.)

At the meeting of the Board of Estimate and Apportion-
ment on December 10, 1909, the committee appointed on De-
cember 3 reported as then directed. The majority report of
the committee (page 35) endorsed the plan of the Board of
Water Supply, and the Hon. Lindon Bates, Jr., submitted a

minority report. (See page 41.) This minority report, while
criticizing the general plan, offered no suggestions for an alter-
native. Thereupon the Board of Estimate and Apportionment
by resolution (page 43) approved the plan of the Board of
Water Supply for the deep pressure tunnel.

Immediately on the approval of this plan by the Board of
Estimate and Apportionment, as required by statute, petition
was made for its approval to the State Water Supply Com-
mission. (See pages 45 and 47.) On December 16, 1909, the
State Water Supply Commission gave public notice of the
filing of the plan for the pressure tunnel and fixed January
12, 1910, as the date for a public hearing in this matter. (See
page 55.)

The Board of Estimate and Apportionment at its meeting
of January 7, 1910, adopted a resolution requesting the State
Water Supply Commission to defer final action upon any pro-
jected extensions or modifications of New York's water supply
system (page 57). The matter then rested until March 4, on
which day the Board of Estimate and Apportionment adopted
a resolution calling for the appointment of three of its mem-
bers, with instructions to examine into the engineering feasi-
bility of the proposed pressure tunnel and to report thereon
(page 59). In compliance with this resolution, the Mayor
appointed as members of this committee the President of the
Board of Aldermen, the Comptroller and the President of the
Borough of Manhattan.

The committee of the Board of Estimate and Apportion-
ment retained as expert advisers two engineers and a geologist.
These advisers reported (page 60) in favor of the plan of the
Board of Water Supply and concluded their report in the fol-
lowing words:

" We have been greatly pleased — some of us have been
agreeably surprised — at the extensive and able study that this
project of a Manhattan pressure tunnel has already received.
Besides replying to the specific questions put to us as we have
done, we > desire again to say that, whether viewed from the
point of first cost, maintenance or of future cost, our opinion
is that The City of New York will do well to direct the imme-
diate construction of the proposed Manhattan pressure tunnel,
for purposes of distributing the Catskill water-supply to the
five boroughs."

Thereupon the committee of the Board of Estimate and
Apportionment, under date of June 27, 1910, reported to the
Board at its meeting of July 1, 1910 (page 103). The follow-
ing quotation is made from the report of this committee :

" In conclusion, your Committee is impressed with the fact
that in scientific authority, in the reliability of experienced
engineers and contractors, in careful and unprejudiced analysis,
and in ordinary common sense, the weight of the arguments
we have received is overwhelmingly in favor of the soundness
and economy of the plan of the Board of Water Supply, and
we would recommend that the Board approve of the plan and
profile of the Board of Water Supply dated November 15,

1909, that it direct the Comptroller to issue corporate stock of
The City of New York to an amount not exceeding $25,000,000
to meet the expense of carrying out the plan, that the resolu-
tion of this Board of January 7, 1910, requesting the State
Water Supply Commission to suspend action on the said plans,
be rescinded, and that the State Water Supply Commission be
notified of this action. A resolution to this effect is herewith

submitted."

The Board of Estimate and Apportionment then, on July 1,

1910, adopted a resolution approving and authorizing the plan
of the Board of Water Supply for the deep pressure tunnel
and directing the Comptroller to issue bonds in an amount not
exceeding $25,000,000 for the uses and purposes of the Board
of Water Supply. (See page 108.) This resolution also
rescinded that of January 9, 1910, which requested the State
Water Supply Commission to defer final action.

The way now being clear, the State Water Supply Com-
mission, *after public hearings on July 13 and 14 and after care-
ful study, decided that the proposed plan was wise, feasible
and economical. It therefore, on October 20, 1910, granted
the petition and approved the plan (page 109) for the following
reasons :

(1) That the plans were justified .by public necessity.

(2) That the plans were just and equitable to other muni-
cipalities and civil divisions of the state.

(3) That the plans made just and equitable provisions for
the determination and payment of any and all damages to per-
sons and property.

8

In the meantime studies and designs leading to the prepara-
tion of contract specifications and drawings had progressed
so far that it was possible to advertise four contracts for the
tunnel on December 8, 1910. The advertisements were, how-
ever, recalled on December 13, 1910, and it was not until
April 13, 1911, that the approval of the Corporation Counsel
was received and the contracts finally advertised. Bids were
opened May 16, 1911, and on May 26 and June 5 the four
contracts, covering the tunnel portion and totaling $19,100,000,
were awarded to the lowest bidders. (See canvasses of bids,
page 114).

The work to be done comprises a circular tunnel in solid
rock reducing in diameter from 15 feet to 14, 13, 12 and
11 feet along the route from the Hill View reser-
voir through the Boroughs of The Bronx and Manhattan to two
terminal shafts in Brooklyn, from which 66-inch steel pipes,
reducing to 48-inch cast-iron pipe-lines will extend into Queens
and also into Richmond. Two 36-inch cast-iron pipes, rest-
ing on the harbor bottom, will cross the Narrows to the Silver
Lake reservoir of 400,000,000 gallons capacity on Staten Island.
The total length of this delivery system is over 34 miles. The
detailed location is* shown on map entitled " Catskill Aqueduct,
City Tunnel and Pipe-Lines."

The tunnel will be at depths from 200 to 750 feet below
the street surface, thus avoiding interference with street traffic,
buildings, subways, sewers and pipes, and providing a substan-
tial rock cover to withstand the bursting pressure*, and will be
constructed from 24 shafts spaced at distances of about 4,000
feet apart, located in parks and other places where little inter-
ference with traffic will result. Through these shafts, also, the
water will be delivered by means of suitable connections into
the existing water-mains. All of the tunnels and shafts
will be lined with concrete. The estimated cost of. this entire
distribution system to all of the boroughs, including the tunnel,
the pipe-lines and the Silver Lake reservoir, is $25,000,000, an
increase of $15,000,000 over the amount included in the orig-
inal plan, which provided only for the delivery of water to the
Boroughs of Brooklyn and Richmond.

Up to August 1, 1912, 20 of the 24 shafts of the pressure
tunnel had been sunk to their final depth, and work on the
remaining 4 was well advanced. To this date over three miles
of the tunnel have also been driven.

October 1, 1909.
Mr. J. Waldo Smith,

Chief Engineer.

Dear Sir:

In accordance with your verbal instructions, I beg to report
on the type and general location of conduits to be adopted for
the delivery of the Catskill Mountain water to the various
boroughs, this report embodying the results of the investiga-
tions made during the past year, corrected to October 1, 1909.

To deliver the Catskill supply from Hill View reservoir
to the five boroughs, one or more conduits must be built, as
the main pipe-lines of the present distribution systems are
barely sufficient to deliver the amount of water required at
present and cannot carry any portion of the new supply.

To carry this supply either metal pipe or rock tunnels must
be adopted, as the pressures are too great to be withstood by
reinforced concrete pipes. The pressure tunnel system has the
following advantages over m&tal pipes:

(1) Lower first cost.

(2) Lower annual charges for interest, sinking fund for
redemption of bonds, depreciation charges, repairs and main-
tenance.

(3) Non-interference with street surface during construc-
tion and with use of subsurface for subways, sewers and other
structures.

(4) No deterioration, and therefore, no repairs with re-
sultant interference with surface and tearing up of streets.

(5) Interference with use because of breaks, reduced to a
minimum.

(6) Practically no disturbance to streets during construc-
tion.

(7) Possibility of delivering along any point on the tunnel
line a quantity of water greater than could be used in checking
any threatened conflagration.

(8) Adequate cross-connection of all distribution systems,
so that any system could be temporarily put out of service and
its territory supplied by other systems.

The conduit system recommended consists of a single pres-
sure tunnel from Hill View reservoir, passing under the Bor-

10

oiigh of The Bronx at an elevation of about 30 to 40 feet
below tide-water, dropping at the Harlem river to a depth of
about 350 feet, and continuing at this depth until Manhattan
valley is passed, rising then to an elevation of about — 100 and
continuing with a slightly descending grade to the east side of
Manhattan, where the invert is dropped to an elevation of
— 600 to avoid weak rock which is found near the surface,
the crossing into Brooklyn being at a depth of about 250 feet
below the East river, and the tunnel terminating at about La-
fayette and Flatbush avenues. Pipe-lines from 66 to 36 inches
in diameter are to be run to the Boroughs of Queens and Rich-
mond.

At each shaft, that is about every 4,000 feet, connections
are to be made to the distribution system by means of pressure-
regulating and control valves so that the water can be delivered
into the pipes at either full or reduced pressure, as may be
found advisable.

With the exception of a few hundred feet at the northerly
end, the tunnel is to be 15 feet in diameter as far south as
135th street, or the point where the present Croton tunnel
terminates, thus making it practical to put out of service tem-
porarily the Croton tunnel and deliver the water through the
proposed Catskill tunnel. Between 135th and 40th streets the
diameter will be 14 feet; between 40th and 24th streets 13 feet;
between 24th and Delancey streets 12 feet; and from Delancey
street to the terminal in Brooklyn 11 feet. The pipe-lines are
to start as 66-inch steel pipes and reduce to 48-inch cast-iron
pipes for the line to the Borough of Queens, and to 48-inch
cast-iron pipes for the line to the Borough of Richmond, a
36-inch submerged pipe being used for the Narrows crossing
with a 48-inch connection to the Silver Lake reservoir.

The combined tunnel and pipe-line system is shown on
Sheet 2, Ace. 15492, and the pipe-line system on Sheet 3, Ace.
15493.

The proposed pressure tunnel is to be of equal capacity to
the aqueduct now being constructed to carry the supply from
the Catskill mountains to Hill View reservoir, and by increas-
ing the loss of head, a much greater quantity can be delivered.
The tunnel is to be located through the Boroughs of The Bronx
and Manhattan and into Brooklyn, and the outlets are to be

11

of ample capacity to serve any one of the boroughs or such
portion thereof as may be deemed advisable.

With such large conduit capacity and comparatively small
increased frictional head resulting from increased velocity, it
is unnecessary to provide equalizing reservoirs in the various
boroughs with the exception of the Borough of Richmond,
where a reservoir is provided both to equalize the pressure and
safeguard the supply, this borough being dependent upon one
or more submerged pipe-lines which would require time to
repair and which are more liable to failure than lines laid
under streets.

As the conduit system is kept mainly within street and park
limits, there will only be about 1,700 feet of private right-of-
way to be acquired, and all shafts except two are to be on City
property.

If work is prosecuted actively and continuously, about four
years will probably be required for construction.

The estimated costs of the combined tunnel and pipe-line
system and of the pipe-line system, in both cases omitting the
reservoir in Richmond, are as follows:

Q Construction Cost Reduced to

aYSTEM Cost Present Worth Basis

Tunnel and pipe-line $23,400,000 $22,400,000

All pipe-line 47,100,000 36,200,000

GENERAL CONDITIONS GOVERNING DELIVERY

OF CATSKILL WATER

Catskill water, supplemented by that obtained from the
Croton, Bronx and Byram watersheds, is the logical supply
for the Boroughs of Manhattan and The Bronx. For the
Boroughs of Brooklyn, Queens and Richmond the source of
additional supply will depend partly upon the action taken
in relation to the Suffolk County watershed. Even if this
watershed is made available, a portion of the Catskill supply
should be delivered to Brooklyn, Queens and Richmond.
Cross-connection of all water-supply systems of the City is
necessary to utilize to the best advantage the storage in the
various watersheds, to give flexibility in distribution and to

12

safeguard against serious interruption in any supply. With
such a connection the Long Island water might be used as
an emergency supply for Manhattan, or the Croton water for
Brooklyn.

The comparatively high elevation at which the Catskill
water will be delivered, makes it available for the territory
at present served by the Williamsbridge, Bronx high, and Man-
hattan main and upper high services, thus eliminating the ex-
pense of the pumping-stations connected with these services.
The balance of the supply from the Catskill works can be
used in The Bronx and Manhattan, where the Croton supply
does not give adequate pressure and where house pumps are
used, in the higher services of the Boroughs of Brooklyn and
Queens, and in Richmond. This distribution of the water
would result in saving nearly $2,000,000 annually „ which is
expended for maintaining and operating public and private
pumping-plants.

LOCATION OF DELIVERY CONDUITS

Conduit lines should pass through or terminate in those
districts where the water is to be used, the location depending
on the consumption and conditions affecting construction.

The water consumption of the Boroughs of Richmond,
Queens and The Bronx approximates 60,000,000 gallons daily,
while in Manhattan and Brooklyn it is over 450,000,000 gal-
lons daily. Manhattan and Brooklyn will, for many years to
come, require the greater part of the water-supply, only a
small percentage being used for the other boroughs. The popu-
lation of Manhattan will probably cease to increase within the
next 20 years, but the water consumption of that borough is
not mainly due to the resident population but to use in build-
ings devoted to manufacturing, offices and other business pur-
poses. The amount of water required will probably continue
to increase, even after the population decreases. If large con-
duits are constructed from Hill View reservoir through the
Boroughs of The Bronx, Manhattan and Brooklyn, and con-
nected with the Long Island distribution system, they will
traverse the territory of maximum consumption and efficiently
distribute the supply. This route would be economical for a

Harlem River crossing. Ho!t
diameter; 9'

tobcr 13. 1909.

13

pressure tunnel system. Cost and difficulties of construction
in the Borough of Manhattan would make the Bronx-Queens-
Brooklyn route advisable for a pipe-line system to transport
the water to Queens, Brooklyn and Richmond. The two routes
have been investigated and tentative conduit line locations
made, as shown on Sheets 2 and 3, Aces. 15492 and 15493.

The practicability of the Bronx-Manhattan-Brooklyn pres-
sure tunnel is dependent upon the borings showing suitable
ledge-rock. Professor Kemp and Dr. Berkey, the geological
experts, reported before the borings were commenced that
probably a satisfactory rock formation would be encountered
along the proposed tunnel line. This opinion has been sub-
stantiated by the hundred or more borings made along, and in
the vicinity of, the proposed line, some of the borings being
about 25 feet apart where uncertain formation was expected.
The location and elevation of the tunnel have been fixed by the
rock condition and street and park alinement. Sound rock
comparatively near the surface has been found along the en-
tire line except under the Harlem river, Manhattan valley and
the lower east side of Manhattan. Under the Harlem river
the soft rock was found at the contact between the limestone
and Manhattan schist to a depth of about 160 feet, or about
the same as found when the New Croton tunnel was driven
under the river about 1,500 feet north of the proposed cross-
ing. At a depth of 200 feet a sound contact was found and
the tunnel is to be nearly 200 feet below this sound contact.
Under Manhattan valley, schist was found about 200 feet be-
low the surface; but six holes put down within a space of
two blocks did not indicate any disintegration of the rock.
Under the lower east side the borings made have shown sound
rock to be from 300 to 400 feet below the surface, but no
indication that sound rock cannot be found at reasonable depths
for tunneling. The deep rock valley is narrow, so that the
shafts on each side could be sunk in sound Fordham gneiss
which is near the surface, and the tunnel would cut the rock
200 or more feet below the sound rock floor. Under the East
river and in Brooklyn the most impervious and durable rock
along the entire line has been found. The rock floor in Brook-
lyn probably slopes downward to the southeast preventing
carrying the tunnel beyond the proposed terminal at Lafayette

14

and Flatbush avenues. It also would not be economical beyond
this point, due to the divergence of the necessary lines of dis-
tribution and the comparatively small quantities to be carried.

SIZE OF CONDUITS

The magnitude of the Catskill supply necessitates the use
of larger conduits than those normally employed for delivery
purposes, and it is advisable to adopt conduits of the maximum
diameter that can be laid in City streets without seriously inter-
fering with or endangering other structures. In New York
City any large pipe-lines will interfere with sewer pipes, elec-
tric ducts, water-mains and gas-mains, and after a certain
diameter is reached, the sewer system would have to be re-
modeled and grades changed. While these obstacles are im-
portant, the most important factor is the construction of sub-
ways. Manhattan island will, at some time in the future, un-
doubtedly have subways in practically all the north and south
avenues, while The Bronx will also have many of its streets
occupied by subway structures. The danger of damage to
life and property increases with the size of pipe, and the usual
practice limits the diameter of street mains to 48 inches. It is
not prudent to increase the diameter of steel pipes beyond
60 to 66 inches. The sewer grades in The Bronx make it
impracticable to lay mains larger than 66 inches in diameter
without replacing the sewers, and this size has been adopted as
the maximum to be considered. For pressure tunnels, the
size is practically unlimited, as the conduit would be entirely
in bed-rock and at an elevation below any present or proposed
subsurface structure. The only interference with subsurface
structures would be at shaft sites, and as these would be located
approximately 4,000 feet apart, and in parks or side streets,
they would not be serious obstructions.

POSSIBLE TYPES OF CONDUIT CONSTRUCTION

The main factors in determining the type of conduits are :
safety from failure, permanence, cost, interference with sur-
face and subsurface structures during construction and after
completion, interference with traffic during construction, and
freedom from disturbance by future construction. The types

; working under Con t rat

15

to be considered would be reinforced concrete, cast-iron or
steel pipes, or lined tunnels driven in the ledge-rock. The
use of reinforced concrete would be limited to sections where
the pressure would not exceed, approximately, 30 pounds, and
therefore this type of construction would not be suitable to
meet the conditions in Greater New York. From the view-
point of safety from failure, cast iron is not satisfactory, owing
to its unreliability, especially for large pipes under heavy pres-
sure. Steel would be reliable until deterioration due to corro-
sion had weakened the metal sufficiently to cause fracture. A
pressure tunnel constructed in the rock at a grade well below
that of other subsurface structures would be safe from failure,
and the only possibility of a break interfering with the supply
from the tunnel would be at the points of connection, which
would be at each shaft site. For safety in operation, the type
of conduit to be adopted would be pressure tunnel. This type
would be the only permanent one, as corrosion and electrolysis
make indefinite and uncertain the life of metal pipes and at
some time necessitate their replacement. In comparing relative
economy of conduits, it is necessary to consider their capacity
with the same hydraulic gradient and their cost per unit of
length. This comparison for cast iron, steel and pressure
tunnel would be as follows:

Conduit •

Size

Nominal
Capacity
Million
Gallons
Daily

Construction

Cost

per Foot

Resultant Cost

per Foot per

Million Gallons

Daily

Capacity

Cast iron

. . . 48 inches

19

32

500

$35.00

40.00

250.00

$1.84

Steel

Pressure tunnel

... 15 feet

1.25
.50

There can be no question as to the economy of pressure tun-
nels over pipe-lines where large quantities of water are to be
delivered and rock conditions are favorable. Deferment in
installation of pipes would reduce somewhat the apparent dif-
ference in cost, but only slightly. If the maintenance and an-
nual charge basis be used for comparison instead of the con-
struction cost, the difference would be still more striking.

Interference with present and prospective structures, both
above and below the surface of the street, is reduced to a
minimum by the construction of a tunnel, while a large num-

16

ber of pipe-lines would prevent the building of subways and
other subsurface structures in streets where the pipe-lines were
installed. A pressure tunnel has a manifest advantage over
pipe-lines during construction, in the slight amount of incon-
venience caused to traffic and business, due to the work being
carried on below the surface. This advantage might not be
important if only one pipe-line were to be laid, but where
approximately 16 pipes, 66 inches in diameter, or 30 pipes
48 inches in diameter, would be required instead of one pres-
sure conduit, its value is manifest. The pipe-lines would have
a slight advantage from a distribution view-point, in reducing
the mileage of smaller connecting mains and in splitting up
the conduits into a large number of parts and thus. making it
possible for one or more units to be put out of service without
seriously affecting the whole system. It is hardly conceivable
that the tunnel itself can fail, and at the shafts, special safe-
guards will eliminate practically all chance of having to shut
down the tunnel due to a break in any appurtenance. On ac-
count of their comparatively short life, the pipe-lines would
require the tearing up of streets at intervals of about 35 years,
whereas the tunnel would last indefinitely. There would also
be a period of years immediately preceding the replacement
of pipe-lines when breaks would be comparatively frequent,
due to the difficulty in determining the actual condition of the
mains. Serious damage to property, and possibly to life, might
result from such failures of the pipes.

Where the total amount of. water to be carried exceeds
150,000,000 gallons daily, a pressure tunnel is both economical
and desirable for New York City conditions, if the geological
formation permits of such construction.

ECONOMIC SIZE OF PRESSURE TUNNEL •

In determining the probable diameter of pressure tunnel
that will give the most economical results, it is necessary to
consider the relative cost of tunnels of different diameter,
and the time when the maximum capacity of a conduit of
any given size will be utilized by the increase in consumption.
The studies made have been based on the estimated cost of
tunnels, on the capacity with a gradient of three feet per mile,
and on the probable consumption in the various boroughs.

17

The theoretical present worth of the construction costs of
tunnels from 12 feet to 16 feet 6 inches in diameter have been
computed, as an aid in fixing the economic size of a single
tunnel. In making these computations, it has been estimated
that when the consumption equals the nominal carrying ca-
pacity of the tunnel, after allowing 15 per cent, for hourly
fluctuation in flow, a second tunnel of equal size would be
constructed. The results of these studies show that there is
little difference in economy when the diameter exceeds 14 feet
6 inches. The factors involved in the question of size are not
sufficiently well defined to permit of an accurate solution of
the problem, and a tunnel of any diameter from 14 feet
6 inches to 16 feet 6 inches might be chosen with little, if any,
difference in the ultimate cost to The City.

It is proposed to carry the tunnel of the 15-foot size under
the Harlem river and south to 135th street, where connection
will be made with the Croton gate-house, the 14- foot size being
carried to 40th street, where the convergence of important rail-
way lines indicates a concentration of large, high buildings,
requiring many million gallons of water per day. The 13-foot
tunnel is to be carried to 24th street, where connection will
be made with numerous large distribution pipes. The 12-foot
tunnel terminates under Delancey street near the Bowery,
and an 11-foot tunnel has been adopted to cross under the
lower east side of Manhattan, to supply Brooklyn. A tunnel
of this size will carry approximately 290,000,000 gallons daily,
and the cost would be about 8.5 per cent, greater than that for
a 10-foot tunnel, whereas the carrying capacity would be about
26 per cent, greater. It is therefore practical to obtain the
larger conduit capacity at a comparatively slight increased ex-
penditure. Furthermore, with the additional conduit capacity
under the East river, it would be practicable to draw, from
time to time, more heavily on the gravity sources and reduce
the amount pumped from Long Island, thereby saving the
cost of pumping, and also, in an emergency, deliver all the
water required for Brooklyn through the tunnel. The eco-
nomic size cannot be mathematically determined, and the size
to be adopted is mainly a question of judgment.

In the extension of the aqueduct south of Hill View reser-
voir, it is possible to deliver an additional amount of water

18

over and above the assumed capacity of the aqueduct, by in-
creasing the loss in head. It is probable that the pressure
tunnel below Hill View reservoir will at times be called upon
to deliver a much greater quantity of water than the normal
capacity of the Catskill aqueduct. It will therefore be advis-
able to construct this aqueduct of as large size as can eco-
nomically be adopted, and thus defer the installation of a
second tunnel for many years. To illustrate the increased
loss in pressure that would be due to the adoption of a smaller
tunnel than the one proposed, estimates have been made which
show that a tunnel starting at 13 feet and reducing to 10 feel
in diameter would increase the loss in head by 75 per cent.,
while a tunnel starting at 12 feet and reducing to 9 feet in
diameter would increase it by 150 per cent. The correspond-
ing decreases in cost would be 10 per cent, and 15 per cent.
The loss in head would show still greater proportional differ-
ence if the quantity to be carried was materially increased.
The proposed tunnel gives practically the same loss in head
as the Catskill aqueduct would give for an equal distance.

EFFECT OF PROPOSED SYSTEM ON SYSTEM FOR

BROOKLYN AND RICHMOND OUTLINED

IN REPORT OF OCTOBER 9, 1905

In the report of 1905 an estimate was made of the cost of
pipe-lines necessary to carry 100,000,000 gallons daily from
Hill View reservoir to Forest park, Brooklyn, and 20,000,000
gallons daily to Richmond. This plan consisted of a single
large steel pipe through The Bronx, crossing under the East
river in tunnel and dividing in Queens into two mains, one
running to Forest park and the other to Richmond. The esti-
mated cost was $10,224,000.

Under this plan water would be delivered at Forest park
at Elevation 180 and at Richmond at elevation of about 120,
the loss in head from Hill View reservoir to Brooklyn being
110 feet and to Richmond 170 feet. Necessary reservoirs in
Forest park and Richmond would add from $4,000,000 to
$5,000,000 to this cost, as, due to the very high velocities in
the pipe-lines, practically no additional supply could be deliv-
ered to take care of the hourly fluctuation in consumption.
Of the nominal 500,000,000 gallons daily to be supplied from

19

Cat skill sources, only conduit capacity for 120,000,000 gallons
daily was provided for south of Hill View reservoir, and
over three times this amount, or 380,000,000 gallons daily, had
to be delivered to The Bronx, Manhattan, Queens and Brook-
lyn. The amounts required for each borough are estimated
approximately as 80,000,000 gallons daily for The Bronx,
200,000,000 gallons daily for Manhattan, 40,000,000 gallons
daily for Queens and 60,000,000 gallons daily for Brooklyn.
In designing the most economical system to handle the
380,000,000 gallons daily, it was found that by including the
120,000,000 gallons daily in a tunnel system, the water could
be delivered to Brooklyn and Richmond for approximately half
what it would cost under the 1905 plan, and the loss in head at
the point of consumption would be reduced by about 100 feet.
The system covered by the 1905 report has therefore been
modified by including it in the tunnel plan.

TYPE OF CONDUIT CONSTRUCTION SUITABLE
FOR THE VARIOUS BOROUGHS

The Bronx
The consumption in the Borough of The Bronx will not
be of sufficient amount to materially affect the type or size
of the conduit necessary to distribute the water from the Hill
View reservoir. The geological conditions are favorable to
the construction of a pressure tunnel. Parks, street intersec-
tions and other public property provide suitable shaft sites.
It has been assumed that one 15-foot tunnel will be constructed,
having a capacity of about 630,000,000 gallons daily, with a
hydraulic gradient of three feet to the mile. This would be
equivalent to the maximum hourly consumption with an
average consumption of 500,000,000 gallons daily.

Manhattan

The arguments in favor of a pressure tunnel apply espe-
cially to the Borough of Manhattan and also to the crossings
under the Harlem and East rivers.

Brooklyn

The amount of water to be carried to any section of Brook-
lyn is hardly sufficient to make a pressure tunnel economical

20

beyond the river front. Furthermore, the geological condi-
tions preclude the possibility of economically constructing a
tunnel for any considerable distance under Brooklyn, and it is
therefore proposed to carry the tunnel on the Brooklyn side
for only a few thousand feet from the river front. Steel or
cast-iron pipes would be used to carry the necessary supply
for Staten Island through Brooklyn to the Narrows, connec-
tions being made from this line to the high service sections
in the vicinity of Prospect park.

Queers

Comparatively small mains will be required for the Borough
of Queens, and these will be either of steel or cast iron, as
detailed study may indicate to be advisable. It will probably
not be necessary to lay mains larger than 48 inches in diameter
for this service.

Richmond •

The supply for this borough must be carried under the
Narrows and owing to the excessive depth to rock, it will be
advisable to lay some form of submerged pipe-line. There are
no special difficulties to be anticipated in the construction of
such a line, except the number and size of the vessels passing.
There might be some danger of a break in the line, due to ves-
sels dragging their anchors and fouling with the pipe-line,
or the explosion of mines in war time destroying a section of
the pipe. As the pipe would be laid 20 feet or more below the
bottom of the harbor, the danger from anchors is slight.

The building of a large equalizing reservoir in Richmond
will maintain the supply for several weeks and give an oppor-
tunity to repair any break in the main. One 36-inch main is
proposed for the Narrows crossing, it being expected that this
main would be duplicated in about 1925, as the increase in
consumption by that time would warrant the construction of
the second main as a safeguard, although the one main would
be of sufficient capacity to deliver the required supply.

EOUALIZING RESERVOIRS

In the Borough of Brooklyn the Ridgewood reservoir af-
fords ample capacity to meet the requirements of the low serv-
ice. There is no available reservoir site for the Catskill service

I

£

i

i

i

I

k

1

I

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I*

i
I

!

i

i

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21

in Brooklyn which will deliver water at a sufficiently high
elevation to feed both the present Mt. Prospect high and low
services. The Mt. Prospect tower could be used as a relief
valve on this new service, which would supply the territory
fed by the present Mt. Prospect services.

In the Borough of Queens, the Ridgewood reservoir would
be satisfactory for the low service, and until the higher ground
is much more densely populated than at present, it would not
be necessary to provide a reservoir, the existing stand-pipes
being sufficient for the needs of the system,. When the high
sections of the borough are extensively built up, it will prob-
ably be advisable to construct a reservoir of sufficient capacity
to maintain an approximately uniform hydraulic gradient
throughout the day, but it will be many years before this res-
ervoir is needed.

For the Borough of Richmond, studies were made of avail-
able sites and the cost of reservoirs in Silver Lake and Clove
Lake valleys was estimated. A reservoir in the Clove Lake
valley would give a storage of about 900,000,000 gallons. This
reservoir could only be used for an emergency supply, owing
to its low elevation. On the Silver Lake site, a reservoir
with a flow-line of 225 feet would have a capacity of about
400,000,000 gallons, and this reservoir would cost somewhat
less than one at Clove lake. The Silver Lake reservoir could
be used as an equalizing basin in connection with the Catskill
supply, and its construction is therefore recommended. The
estimated cost of the reservoir, including land, is $1,260,000.

TIME REQUIRED FOR CONSTRUCTION

The time necessary to complete the delivery system will be
determined by the difficulties that may be encountered in driv-
ing 5,000 feet of tunnel, as this distance will represent the
probable maximum distance between shaft sites. Assuming
an average rate of progress of eight feet per day in each head-
ing, or a total of 16 feet per shaft, it would require about one
year to drive a section. To this must be added about 2*/2
years for assembling of plant, sinking shafts, concreting of
tunnel, and completion of connections, thus allowing 3^2 years
for actual work. From six months to a year must be allowed
for the collection of necessary information and preparing and

22

letting of contracts. The tunnel might be completed in say
four years, or possibly in less time by strenuous endeavors
and good fortune. It would hardly be safe, however, owing
to delays from uncertain causes which cannot be predicted but
which almost always occur in the prosecution of New York
City work, to estimate on the completion of all portions of the
tunnel, within four years.

ESTIMATED COST

Estimates have been made of the cost of the combined tun-
nel and pipe-line system and of the pipe-line system, basing
the cost for the tunnel on the bids received for similar work
along the Catskill Aqueduct line, and making allowance for
additional cost for handling the spoil within City limits. These
estimates have been checked by comparing prices paid for a
sewer tunnel in The Bronx and one just north of the City line,
work on these tunnels being now under way. The estimates
used herein exceed, by 10 per cent, or more, the sewer tunnel
prices. The pipe work has been estimated on prices based
on City contracts.

COMBINED TUNNEL AND PIPE-LINE SYSTEM

Pressure Tunnel

Size of Tunnel

Length
Miles

Cost per
Mile

Total Cost

15 feet

0.40
7.31
4.94
0.40
1.36
3.24

$1,160,000
1,030,000
950,000
870,000
820,000
770,000

$460,000
7.540.000
4,700,000
350,000
1.120.000
2,500.000

150,000
250,000

$17,070,000
3.414,000

14 feet

13 feet

12 feet

11 feet

Easements, right-of-way,

20 per cent, for engineers

•

$20,484,000

Pipe-Lines

Size of Pipe

Length
Miles

Cost per
Mile

Total Cost

66-inch steel

2.4 $164,000

10.5 121.000

to 137,000

1.7 100,000

2.0 264,000

$394,000

1,400,000
170,000
528,000

$2,492,000
374,000

15 per cent, for engineeri
Total

$2,866,000
$23,850,000

—

._ _ __

k

23

PIPE-LINE SYSTEM
Pipe-Lines'

Ct , B __ ,>,„„ Length Cost per

Size of Pipe Miles Mile

66-inch steel 210. 5 $164,000

to 214,000

66-inch submerged 0.3 345,000

48-inch cast iron 3.8 137,000

36-inch cast iron 1.7 100,000

36-inch submerged 2.0 264,000

15 per cent, for engineering and contingencies

Total Cost

$38,500,000
104,000
521,000
170,000
528,000

$39,823,000
5,973,000

$45,796,000

Pressure Tunnel

Size of Tunnel

Length
Miles

Cost per
Mile

Total Cost

10 feet.
8 feet.

0.8
0.5

$890,000
700,000

Easements and right-of-way.

20 per cent, for engineering and contingencies.

Total ,

$710,000
350,000

50,000

$1,110,000
222,000

$1,332,000
$47,128,000

In the preceding estimates no allowance has been made for
the reservoir in Richmond, which is estimated to cost, includ-
ing engineering and contingencies, about $1,300,000.

After making due allowance for possible deferment of
installation of pipe-lines, the present worth of the bond issues
is as follows:

Combined tunnel and pipe-line system . . . . $22,400,000

Pipe-line system 36,200,000

As these two systems accomplish practically the same re-
sults in delivering the water to the various boroughs, the com-
bined tunnel and pipe-line system is the more economical.

Respectfully submitted,

WM. W. BRUSH,

Department Engineer.

SHEET 2

City of N«w York

BOARD OF WATER SUPPLY

CATSKILL AQUEDUCT

CITY TUNNEL AND CONDUITS
TUNNEL AND PIPE LINES

Ijlrfi IM i

MARCH. 190*

File D 5.4 Cy Ace 1 5492

M. ft. BROWN PRINTING It BINDING CO., N. Y

SHEET 3

CATSKILL
AQUEDUCT

City of Now York

BOARD OF WATER SUPPLY

CATSKILL AQUEDUCT

CITY CONDUITS
PIPE LINES

IMi

5*

DECEMBER, 1908

File D5.4CM Ace 1 5493

M. 8. BROWN PRINTING * BINDING CO., N. V

25

BOARD OF WATER SUPPLY
CITY OF NEW YORK
ENGINEERING BUREAU
299 BROADWAY
I. A. Bensel
Charles N. Chadwick
Charles A. Shaw

Commissioners
J. Waldo Smith

Chief Engineer
C. L. Harrison

Deputy Chief Engineer

New York, November 1, 1909.

Board of Water Supply,

299 Broadway, City.

Gentlemen :

I transmit herewith a plan for the delivery of water to the
several boroughs of The City of New York. This plan modi-
fies that portion of the plan of October 9, 1905, approved by
the Board of Estimate and Apportionment on October 27,
1905, which lies between Hill View reservoir and the Boroughs
of Brooklyn, The Bronx, Queens and Richmond, so that the
line now includes the Borough of Manhattan. This modifica-
tion results in a shorter total length of line of about 5 miles
and provides also for the delivery of more water and at ap-
proximately 100 feet greater pressure to the Boroughs of
Brooklyn, Queens and Richmond, while at the same time it
fully cares for the needs of the Borough of Manhattan. In
these respects it is superior to the plan of 1905.

The plan submitted herewith contemplates the construction
of a pressure tunnel in the ledge-rock from Hill View reser-
voir beneath the Borough of The Bronx, the Harlem river, the
Borough of Manhattan and the East river, to a point in the
Borough of Brooklyn near the East River front, where ledge-
rock drops so far below the surface of the ground as to render
this type of construction impracticable of further extension.
From this point it is proposed to lay metal pipes through the
Borough of Brooklyn to that of Queens and across the Nar-
rows to the Borough of Richmond, where an equalizing reser-
voir of about 400,000,000 gallons capacity, at an elevation of

26

about 225 feet above tide, is proposed as the terminal of this
line.

Shafts for facilitating the construction of the tunnel will
be spaced from 3,000 to 5,000 feet apart throughout its length,
and permanent connections to the distribution pipes in the
streets will be made through them. Connections will also be
made with Jerome Park reservoir and the gate-house of the
Croton aqueduct at 135th street. The pipe-lines through
Brooklyn to the Boroughs of Queens and Richmond will inter-
sect practically all the present main distribution lines in that
borough, and connections to them will be made at such points
as may be found desirable.

The entire length of the tunnel, 17.6 miles, and the con-
necting pipe-lines running to Brooklyn, Queens and Richmond,
a total length of 33.5 miles, including the tunnel, will, with
the exception of about 3,300 feet, be located beneath or through
streets, parks and other City property, so that the necessity
of resorting to condemnation proceedings is almost entirely
eliminated.

The tunnel under the East river will afford a long-desired
and necessary connection between the water systems of two
principal boroughs of The City and so render possible an
interchangeable use, as may be necessary, of the water from
the northerly mountain sources and that obtained from "the
sands of eastern Long Island.

The Boroughs of Manhattan and The Bronx, taken
together, cover a long and relatively narrow strip of land.
They obtain their water-supply from the north and, by reason
of this fact, as well as that of the general north and south
direction of traffic, the main streets, particularly in the Bor-
ough of Manhattan, are already well filled with water and gas-
pipes, electric conduits and other structures on, above and un-
der the surface. It is, therefore, both impracticable and unde-
sirable that a quantity of water, as large as the 500,000,000
gallons per day to be furnished by the Catskill supply, should
be brought into The City by means of metal pipes laid beneath
the surface of the streets. Even in case this method were
more economical, it would not be desirable to introduce pos-
sible barriers into the streets which might interfere with
further extension of the subway or other necessary public uses
of the streets.

The tunnel from Hill View reservoir to the Borough of

SHEEt *

29

BOARD OF WATER SUPPLY

CITY OF NEW YORK

299 BROADWAY

Commissioners
J. A. Bensel
Charles N. Chadwick
Charles A. Shaw
Thomas Hassett, Secretary

New York, November 15, 1909.

Hon. George B. McClellan, Mayor,

Chairman, Board of Estimate and Apportionment,
City Hall, New York City.
Sir:

The Board of Water Supply begs to submit herewith plan
adopted November 15, 1909, which in part is a modification
of that portion of the map approved by the Board of Estimate
October 27, 1905, which provides for the conveyance of the
Catskill water through the Boroughs of Brooklyn, Queens and
Richmond.

The modification is recommended for the reason that a
larger amount of water would be by this plan delivered to the
boroughs above mentioned and under a head about 100 feet
and by a route 5 miles shorter than on the plan previously
approved. Through Manhattan island the plan contemplates
the construction of a pressure tunnel in rock, which construc-
tion will also continue to the Boroughs of The Bronx and
Brooklyn, except where the ledge-rock is at a distance below
the surface too great for such construction. Connection will
be made with the distribution system of the several boroughs
at convenient points. The entire length of the tunnel about
\7y 2 miles, connecting pipe-lines running to Brooklyn, Queens
and Richmond, 33^2 miles including tunnel, will, with the ex-
ception of about 3,300 feet of length, be located through City
property, so that condemnation proceedings are almost entirely
eliminated from construction in the map herewith considered.

Very truly yours,

BOARD OF WATER SUPPLY,

Per Thomas Hassett,

Secretary.

50

BOARD OF

ESTIMATE AND APPORTIONMENT

CITY OF NEW YORK

OFFICE OF THE SECRETARY

277 BROADWAY

New York, November 22, 1909.
Hon. P. J. Scully,

City Clerk,

City Hall, New York.
Sir:

Notice is hereby given that at the meeting of the Board
of Estimate and Apportionment, held on November 19, 1909,
the following resolutions were adopted:

Whereas, The Board of Water Supply of The City of New
York, pursuant to chapter 724 of the Laws of 1905, as
amended, has submitted to the Board of Estimate and Appor-
tionment a report and plan which bears the date of Novem-
ver 15, 1909, and is entitled " Map and profile showing man-
ner of delivering the water to the several boroughs " ; said
map being now on file in the office of the Board of Water
Supply of The City of New York, 299 Broadway, New York
City; now, therefore, be it

Resolved, That the 3d day of December, 1909, at 10.30
o'clock in the forenoon, at Room 16 in the City Hall, in The
City of New York, be fixed as the time and place for a public
hearing upon the said report and plan, and that notice be
given of such public hearing by publication in the City Record,
and in the newspapers designated by the Board of City Record
as official City papers; and be it further

Resolved, That the Secretary of this Board be directed to
give such notices as are provided for in said statute.

Respectfully,

' BOARD OF ESTIMATE AND APPORTIONMENT,

Per Joseph Haag,

Secretary.

31

BOARD OF

ESTIMATE AND APPORTIONMENT

CITY OF NEW YORK

OFFICE OF THE SECRETARY

277 BROADWAY

New York, December 3, 1909.

Hon. J. A. Bensel, Commissioner,

Board of Water Supply, City of New York.

Dear Sir:

At the meeting of this Board held on this day a Committee
was appointed, to consist of an engineer to be designated by
the Board of Water Supply, the Chief Engineer of the Board
of Estimate and Apportionment, the Chief Engineer of the
Department of Finance and Mr. Lindon Bates, Jr., to consider
the proposed modification of the general plan for the develop-
ment of the Catskill water supply which relates to the dis-
tribution system within the City limits, and said Committee
was instructed to report back to the Board of Estimate and
Apportionment by Friday, December 10, 1909.

Respectfully,

JOSEPH HAAG,

Secretary.

32

DEPARTMENT OF

WATER SUPPLY, GAS & ELECTRICITY

OFFICE OF CHIEF ENGINEER

13-21 PARK ROW

John H. O'Brien

Commissioner
M. F. Lough man,

Deputy Commissioner
I. M. De Varona,

Chief Engineer

City of New York, December 6, 1909.

Mr. J. Waldo Smith,

Chief Engineer, Board of Water Supply,

299 Broadway, New York City.
Dear Sir:

Answering your inquiry of the 4th inst., in regard to the
tunnel proposed by you for the delivery of the Catskill water
from Hill View reservoir to the Boroughs of Manhattan and
The Bronx, I beg to state that I am familiar with the general
layout of the tunnel and uptakes proposed at various points
within the Boroughs above mentioned, which I have discussed
with you and your representative, and find that the tunnel
as proposed is adequate for the purpose intended. Further-
more, the loss of pressure will be considerably diminished
and the efficiency of the system correspondingly increased,
both for domestic purpose and fire protection. Lastly, the
cost of maintenance will be practically eliminated and no ob-
struction to traffic or disturbance of subsurface structures
occasioned during the construction. Therefore, if, as I assume
to be the case, sufficient borings have been taken and examina-
tions made to show that the rock formation permits the con-
struction of this tunnel within reasonable time and cost, I am
of the opinion that it is a much cheaper and better method
of delivering the Catskill water into our distribution system
than the plan formerly proposed of effecting this delivery
through large steel pipes laid under our streets and avenues.

Yours very truly,

I. M. DE VARONA,

Chief Engineer.

33

CITY OF NEW YORK

DEPARTMENT OF

WATER SUPPLY, GAS AND ELECTRICITY

BROOKLYN BOROUGH
BUREAU OF WATER

John H. O'Brien

Commissioner
William C. Cozier

Deputy Commissioner
Walter E. Spear

Chief Engineer

Brooklyn, December 8, 1909.
J. Waldo Smith, Esq.,

Chief Engineer, Board of Water Supply,
299 Broadway, New York City.
Dear Sir:

In compliance with your request of December 4, I present
herewith my views regarding the plan proposed by the Board
of Water Supply for the delivery of the Catskill supply to the
Borough of Brooklyn.

In the first place, I cannot too strongly emphasize the
necessity for a connection to Brooklyn by which to convey
from the north a portion of the Catskill supply. With good
fortune, Brooklyn's present sources of supply may suffice for
several years to come, but early relief must be secured from
new sources if a serious shortage of water is to be avoided.

The plan now proposed, as I understand it, provides for a
conduit which has sufficient capacity to deliver 200 to 300
million gallons per day to Brooklyn at a head of 250 to 260
feet above sea level. The location of the proposed conduit
in the center of the downtown manufacturing and commercial
district of Brooklyn will deliver the soft Catskill water, where
it should naturally have its greatest use for industrial pur-
poses, and the design of the conduit will insure an uninter-
rupted service. It will be possible, at a small expense, to con-
nect the proposed conduit to the trunk mains of either the
Ridgewood or Mt. Prospect reservoir services, and there will
be ample head to serve even the higher of these services. The
plan will permit of a large extension of the limits of the Mt.
Prospect service and thus provide an increase in the pressures

34

over large areas now inadequately served by the Ridgewood
or low service.

The large capacity of the conduit leading to Brooklyn from
the proposed Hill View reservoir will permit the delivery of
sufficient water, when required, to meet the entire consump-
tion of this borough for many years to come. This, in my
opinion, is the most important feature of the plan now pro-
posed, as it provides against any possible interruption of
Brooklyn's supply through accident to the Ridgewood trans-
portation works. As I understand the original plan, a pipe
line of only 100 million gallons daily capacity was contem-
plated, and this being laid in the City streets, the supply to
Brooklyn would have been liable to interruption. The daily
delivery of 100 million gallons of water would not have met
the requirements of Brooklyn without the construction of ex-
pensive storage reservoirs in this borough, which are not re-
quired by the present plan.

I beg further to state that the design of the proposed con-
duit contains nothing that has not been worked out elsewhere
and I believe that the conduit as proposed will fully meet the
requirements of service for which it is intended.

Respectfully,

WALTER E. SPEAR,

Chief Engineer

35

BOARD OF ESTIMATE AND APPORTIONMENT
OFFICE OF THE CHIEF ENGINEER

New York, December 8, 1909.

Hon. George B. McClellan, Mayor,

Chairman of the Board of Estimate and Apportionment.
Sir:

Under date of November 15, 1909, the Board of Water
Supply submitted to the Board of Estimate and Apportion-
ment a plan adopted by it on that date which is in part
a modification of the general plan approved by the Board
of Estimate and Apportionment on October 27, 1905 and
which includes additions to that plan by providing for the Bor-
oughs of Manhattan, The Bronx and Queens. A public hear-
ing was given on this new plan on December 3, at the close
of which the matter was referred to a committee consisting of
an Engineer to be designated by the Board of Water Supply,
the Chief Engineer of the Board of Estimate and Apportion-
ment, the Chief Engineer of the Department of Finance, and
Mr. Lindon Bates, Jr., with instructions to report back to the
Board on Friday, December 10.

At the hearing of December 3 a number of objections were
made to the present approval of the plan, these objections
being based almost entirely upon the fact that the details of
the plan were not known by the public and had not even been
presented to the Board of Estimate and Apportionment, that
the communication from the Board of Water Supply did not
contain any estimates of cost, and that in fact there was no
information before the Board of Estimate and Apportionment
or available to the public which would justify the immediate
approval of the plans.

Your Committee has devoted all the time at its disposal to
a study of the plans and the investigations of the Board of
Water Supply upon which they were based.

We beg to state that there is nothing unusual in the fact
that the communication to the Board of Estimate and Appor-
tionment did not contain or was not accompanied by an out-
line of the investigations which have been conducted or the
estimates which have been made, and that the communication
contained simply a recommendation for adoption predicated

36

upon certain results which would be secured by the proposed
modification. To the members of the Committee who are con-
versant with the customary procedure in cases of this kind
this was not surprising, as details rarely accompany communi-
cations to the Board, but are investigated by the technical staff
of the Board or of the Finance Department, whose investiga-
tions and conclusions are submitted to the Board in the form
of reports.

The modification in the present plan and the addition to the
original plan are, briefly, as follows :

The general plan approved in 1905 provided for carrying
the entire Catskill supply to the Hill View reservoir, just out-
side the City limits. It further provided for pipe lines from
this reservoir through the Borough of The Bronx, with a
tunnel under the East River, and through the Borough of
Queens to- a reservoir in the Borough of Brooklyn, with a
further line across the Borough of Brooklyn and under the
Narrows to a reservoir in the Borough of Richmond. No pro-
vision was made for supplying the Boroughs of Manhattan
and The Bronx and Queens. The report accompanying these
first plans distinctly stated that " The main distributing lines
from Hill View reservoir to the Boroughs of Manhattan,
Queens and The Bronx are matters for later consideration/'
and the estimates of cost accompanying the report do not in-
clude such lines. The amended plan provides for the elimina-
tion of the pipe lines from Hill View reservoir to the new For-
est Park Reservoir, in the Borough of Brooklyn, and a new
reservoir in the Borough of Richmond, which pipe lines we
should note contemplate a service with no greater head than
that now furnished in the Borough of Brooklyn. The plan
substitutes for these lines a pressure tunnel through a portion
of the Borough of The Bronx and under a greater part of
the Borough of Manhattan and under the East River to a
point in the vicinity of Flatbush avenue and Lafayette avenue,
in the Borough of Brooklyn, from which point the new supply
would be led to the Boroughs of Queens and Richmond. From
shafts distant about four thousand feet from each other con-
nections would be established with the present distribution
systems of The Bronx and of Manhattan, and also a portion
of the Borough of Brooklyn, while from the end of the tun-

37

nel section would radiate lines serving all of the last-named
borough, the most of which are already in existence.

The Committee believes that the five considerations which
are controlling in a study of these plans are as follows :

First — Time. Could the proposed pressure tunnel with the
pipe line extensions be constructed as quickly as the pipe lines
proposed in the first plan, or could it be constructed within
the time at which Catskill water will be available?

Second — Cost. Will the expense of the proposed plan be
greater or less than that of the original plan when there shall
have been added to it provisions for the Boroughs of Manhat-
tan, The Bronx and Queens?

Third — Practicability. Are there any engineering or con-
struction problems involved in this plan, the solution of which
is doubtful?

Fourth — Effect upon the present distribution system.
Would the admission into present mains and pipes of water
under a head of three hundred feet cause serious damage?

Fifth — Is the pressure tunnel with its pipe line extensions
so located as to meet the probable demands of the near
future ?

The Board of Water Supply has placed at our disposal
full information concerning the progress of work under the
Rondout, Wallkill and Moodna siphons, all of which are tun-
nels fully as deep as the deepest of those in the proposed plan,
and from the progress which has been made in both shafts
and headings, the prediction that the longest section between
shafts could be completed in about a year, while with an allow-
ance of two and a half years for the assembling of plants, the
sinking of shafts, the concreting of the tunnels, and the com-
pletion of connections, appears to justify the prediction that
this tunnel will be available at least as soon as the Catskill
water can be delivered to the City, which is estimated to be
not less than four years.

The question of cost has been considered very carefully in
an investigation made by Mr. William W. Brush, Department
Engineer of the Board of Water Supply, the studies having
been carried on for a year and a half and with careful and
thorough discussion brought down to October 1, 1909, are in-
cluded in a report made by him to the Chief Engineer of the

38

Board of Water Supply. We have carefully studied this
report, as in our judgment the result of the investigations out-
lined will be controlling, not only as to cost, but in a great meas-
ure as to the other considerations already, outlined.

Without going into details it appears that the cost per mil-
lion gallons per day furnished through a pressure tunnel will
be less than half the cost furnished through 66-inch steel pipes,
and considerably less than one-third as much as though fur-
nished through 48-inch cast-iron pipes. Careful detailed esti-
mates further indicate that the actual cost of providing for
250 million gallons per day, which is the present development
of the Esopus watershed now under way, through a pipe line
system providing water for all five boroughs, and economically
designed to take advantage of the mains in the present dis-
tribution system, will be almost precisely that of providing for
500 million gallons per day, or the entire Catskill development
through the pressure tunnel with pipe line extensions as pro-
posed in the amended plan, both estimates being $25,000,000,
to which should be credited, however, the estimate for the
pipe lines shown upon the original plan, which was $10,224,000,
which shows an apparent additional cost of $15,000,000 to
supply the Boroughs of Manhattan, The Bronx and Queens.
It should be remembered, however, that the tunnel now pro-
posed provides for a supply of 500 million gallons per day,
instead of 250 million gallons per day, and at a head estimated
to be 100 feet greater in Brooklyn than was provided for in
the previous plan. If to this original plan for Brooklyn and
Richmond is added a pipe line system for the boroughs not
provided for (for a total quantity of 250 million gallons per
day), it will increase the expense $15,000,000, or the same
amount as for a tunnel plan of 500 million gallons per day
capacity. If 500 million gallons per day were provided for
by pipe lines for all boroughs, the estimated cost would be
$47,000,000. If this amount is credited with the interest on
deferred payment, and assuming that these lines will be added
from time to time as needed, the net expense to the City will
be $36,000,000, which is $11,000,000 greater than the estimated
cost of the present plan.

As to the practicability, we find that the Engineers of the
Board of Water Supply have consulted many engineers of

39

experience, including mining engineers, and that their unani-
mous opinion is that the driving of deep tunnels of the kind
proposed involves no serious problems, and that in view of the
preliminary investigations which have already been made there
is no reason to doubt that the plan is entirely practicable. There
is one point along the line where the borings have not yet
been completed at sufficiently frequent intervals and at the
requisite depth to determine the precise elevation at which the
tunnel must be placed to insure satisfactory rock, but as addi-
tional depth involves no engineering difficulties, it seems safe
to assume that this problem will be readily solved.

There appears to have been some doubt as to the effect
upon the present, distribution system of admitting to it a sup-
ply of water with this greatly increased head. We find, how-
ever, that this has been carefully considered, and that by the
use of pressure control valves the amount of added pressure
in the existing mains can be absolutely controlled and adapted
to any pressure which the street mains or the house plumbing
may be able to stand.

The final consideration concerns the location of the pro-
posed tunnel and its pipe line extensions and their adaptability
to meet the demands of the immediate future. It appears
from the report of Mr. Brush and in statements made to the
Committee that this matter has received very careful con-
sideration, and that the tunnel and the pipe line extensions
have been so located as to cross the present arteries of distri-
bution in the Boroughs of Manhattan and Brooklyn, and that
the present supply could be reinforced or increased with a
minimum of expense as increased consumption may demand
in any locality.

At the hearing before the Board of Estimate and Appor-
tionment on Friday last the great desirability of providing at
the earliest possible date for relief for the Borough of Brook-
lyn or for a physical connection which would permit a rein-
forcement of the supply in either Brooklyn or Manhattan in
case of an emergency from the other boroughs was empha-
sized, and we believe that the tunnel under the East River will
establish a connection of this kind which is much needed, and
will do so in a shorter time than is practicable by any other
method.

40

From the investigations made by your Committee we have
reached the conclusion that the amended plan adopted and
recommended by the Board of Water Supply has not been de-
cided upon without thorough investigation and careful study,
and it is our opinion that an unusually thorough investigation
has been made and that the plan has been the subject of excep-
tionally critical and searching analysis in all its details before
its presentation to the Board, and we would recommend that
it be approved as submitted.

Respectfully,

NELSON P. LEWIS,

Chief Engineer, Board of Estimate and Apportionment.

CHANDLER WITHINGTON,

Chief Engineer, Department of Finance.

J. WALDO SMITH,

Chief Engineer, Board of Water Supply.

BOARD OF ESTIMATE AND APPORTIONMENT
OFFICE OF THE CHIEF ENGINEER

December 9, 1909.
Hon. George B. McClellan, Mayor,

Chairman of the Board of Estimate and Apportionment.
Sir:

The fourth member of the Committee, Mr. Lindon Bates,
Jr., has met with the Committee at all of its sessions, and has
joined in the inquiry, but has declined to concur in the report
or to say to what portions he assents or to what he objects.
He has filed a separate communication to his Honor the Mayor,
which is herewith transmitted, together with the report of the
majority of the Committee.

Respectfully,

NELSON P. LEWIS,

Chief Engineer, Chairman of the Committee.

41

December 10, 1909.

To the Mayor, Chairman, Board of Estimate and Apportion-
ment, City of New York:

Regarding the application of the Board of Water Supply
to the Board of Estimate for permission to alter the line of
the Catskill distribution aqueduct from the present authorized
location through Queens and Brooklyn to a location in Man-
hattan and the type of construction from a pipe system to a
tunnel in general 200 feet and in places 600 feet deep it is to
be noted:

1. That the cost of the tunnel system projected by the
Board of Water Supply, of which all mention was omitted in
their application of November IS, 1909, is estimated at
$25,000,000.

2. That the plan presented by the Board of Water Supply
in 1905, estimated at $10,224,000, which was passed with this
resolution :

Resolved, That the Board of Estimate and Apportion-
ment does hereby approve and adopt said report, and the
map, plan and profile accompanying the same, bearing
the date of October 9, 1905 ; does hereby declare the same
to be the final map, plan or plans approved and adopted
by the Board of Estimate and Apportionment,

was not "final," but failed to provide for bringing water to

Manhattan, The Bronx and Queens.

3. That this new tunnel plan will add $15,000,000 to the
$161,857,000 estimated in 1905 for the Catskill system, unless
economies in costs are made to this amount, which is unlikely
so long as the condemnation " expenses " continue to be over
$40 for every $100 worth of land taken, and the salary and
overhead charges continue excessive.

4. That there are only a " hundred or more borings " on
the profile sheet of the line, between Yonkers and Brooklyn,
with occasional outcrop records. These borings are not suf-
ficient for the purpose of obtaining reliable information as to
the condition of the rock underlying the line of proposed tun-
nel. There is a section of nearly half a mile in the neighbor-
hood of Clinton street, where only one boring, if any, has
reached solid rock and where the contractors gave up work
because of the unexpected depth.

42

5. The possibility of combining an east side, Bronx-to-
Brooklyn passenger subway, with water conduits deserves con-
sideration. At the time the present subway was built, its de-
signer, William Barclay Parsons, most earnestly urged the con-
struction of pipe galleries to carry the City water, gas and
electrical conduits, upon the plea that once a tunnel had been
cut the additional excavation necessary to include these pipes
was comparatively inexpensive. The possibility of co-ordinat-
ing these great City enterprises rather than having each De-
partment tear up streets, dig tunnels and lay pipes irrespective
of what the others are doing, is worthy of careful investiga-
tion.

6. If a volume of leakage commensurate with that econo-
mized in other cities is made available there is a possibility
that only 250 million gallons additional need be provided for
upwards of twenty years. For every year that the expenditure
of $49,000,000 for the second 250 million gallons of Catskill
water and of $47,000,000 for Suffolk County extensions, can
be postponed, there will be a saving in interest, amortization
and maintenance of nearly $5,000,000 annually.

Since the recommendation of the Board of Water Supply,
on which the Board of Estimate is requested to act, embodies
no cost estimate and no exact statement of the work to be
done; since the utilization of subway pipe galleries may be
desirable and a less costly aqueduct practicable ; since the City
has nothing to gain by the immediate authorization of plans
for which further modifications may be desirable, it is recom-
mended that, in accordance with Section 3 of Chapter 724 of
the Laws of 1905, the Board of Estimate " cause such sur-
veys to be made and such further information to be obtained
as it shall deem expedient to enable it to act intelligently in
the premises. ,,

Very respectfully,

LINDON BATES, JR.

43

BOARD OF ESTIMATE AND APPORTIONMENT

CITY OF NEW YORK

Whereas, The Board of Water Supply of The City of
New York, pursuant to Chapter 724 of the Laws of 1905, as
amended, has made such surveys, maps, plans, specifications,
estimates and investigations as it deemed proper in order to
ascertain the facts as to what sources for an additional sup-
ply of pure and wholesome water for The City of New York
exist and are most available, desirable and best for the said
supply, and

Whereas, The Board of Water Supply has reported to the
Board of Estimate and Apportionment under date of Novem-
ber 15, 1909, recommending the approval of a map, plan and
profile dated November 15, 1909, and entitled: "Board of
Water Supply of The City of New York. Catskill Aqueduct.
Map and profile showing manner of delivering the water to
the several boroughs," and

Whereas, The Board of Estimate and Apportionment upon
the receipt of said report and the said map, plan and profile,
and on November 19, 1909, adopted a resolution that Decem-
ber 3, 1909, at 10.30 o'clock in the forenoon, at Room 16 in
the City Hall, in The City of New York, be fixed as the time
and place for a public hearing upon the said report, map, plan
and profile, and that notice be given of such public hearing by
publication in the City Record and in the newspapers desig-
nated by the Board of City Record as official City papers, and
that the Secretary of the Board of Estimate and Apportion-
ment give such notices as are provided for in said statute,
and

Whereas, The Board of Estimate and Apportionment, in
order to afford to all persons interested a reasonable oppor-
tunity to be heard respecting the said report, map, plan and
profile, has given reasonable public notice of such hearing, and,
in addition, has given notice of such hearing by mailing to the
President of the Board of Aldermen of The City of New York
and to the City Clerk of The City of New York, in behalf
of the Counties of New York, Kings, Queens and Richmond,
in which real estate to be acquired is situated, a notice of such
hearing at least eight days before December 3, 1909, there
being no Boards of Supervisors designated as such in any of
said counties, and

44

Whereas, Notice of such hearing was mailed to the Chair-
man and the Clerk of the Board of Supervisors of Westchester
County, at least eight days before December 3, 1909, and

Whereas, The said notice of said hearing was published in
all of the papers specified and referred to above, being the
City Record and The Sun, The New York Times, The Globe,
The Evening Mail, Democracy, Tammany Times and Staats-
Zeitung, the newspapers designated by the Board of City Rec-
ord as official City papers, all of which is evidenced by the
affidavits, certificates and documents filed in the office of the
Secretary of the Board of Estimate and Apportionment, and

Whereas, On December 3, 1909, at 10.30 o'clock in the
forenoon, in Room 16, in the City Hall, in The City of New
York, the Board of Estimate and Apportionment met pursuant
to said notice and a public hearing was given to all persons
interested, and a reasonable opportunity to be heard respect-
ing the said report, map, plan and profile was afforded to such
persons, at which hearing said report, map, plan and profile
were considered and due deliberation was had, now, therefore,
be it

Resolved, That the Board of Estimate and Apportionment
hereby approves and adopts the said report and map, plan
and profile, both dated November 15, 1909, and hereby directs
that the said map, plan and profile be executed, signed, certi-
fied and filed as directed in Section 3 of Chapter 724 of the
Laws of 1905, as amended, and hereby declares the same to be
the final map, plan or plans and profile approved and adopted
by the Board of Estimate and Apportionment as provided for
in said section ; and be it further

Resolved, That an application be made by petition in writ-
ing to the State Water Supply Commission as speedily as pos-
sible for the approval of said report, map, plan and profile,
pursuant to Chapter 56 of the Laws of 1909, being Chapter 54
of the Consolidated Laws known as the " State Boards and
Commissions Law," and that the Corporation Counsel is hereby
requested to prepare such papers and to take such steps with
that end in view as may be proper.

Which was adopted by the following vote :

Affirmative — The Mayor, the Comptroller, the President
of the Board of Aldermen, the Presidents of the Boroughs of
The Bronx, Queens and Richmond and the Acting President
of the Borough, of Manhattan — 14.

Negative — The President of the Borough of Brooklyn — 2.

45

BOARD OF WATER SUPPLY

CITY OF NEW YORK

299 BROADWAY

Commissioners
J. A. Bensel
Charles N. Chadwick
Charles A. Shaw
Thomas Hassett, Secretary

New York, December 15, 1909.

State Water Supply Commission,

Albany, N. Y.
Gentlemen:

We transmit to you herewith petition of The City of New
York for the approval of the report, map, plan and profile,
dated November 15, 1909, approved by the Board of Estimate
and Apportionment of this City December 10, 1909, said map,
plan and profile being entitled " Board of Water Supply of
The City of New York. Catskill Aqueduct. Map and profile
showing manner of delivering the water to the several Bor-
oughs."

We also transmit to you herewith one of the originals of
said map, plan and profile, duly signed by the members of this
Board and by our engineers and by the representatives of the
Board of Estimate and Apportionment.

We also send you herewith copy of report of Department
Engineer William W. Brush to Chief Engineer J. Waldo
Smith, copy of report of J. Waldo Smith to this Board, dated
November 1, 1909, concurred in by Consulting Engineers Free-
man, Burr and Noble, copy of report of a Committee ap-
pointed by the Board of Estimate and Apportionment, dated
December 8, 1909, said Committee consisting of the Chief En-
gineer of this Board, the Chief Engineer of the Board of
Estimate and Apportionment, the Chief Engineer of the De-
partment of Finance of The City of New York.

We also beg leave to refer to you and to present as part
of the City's application, all of the reports, testimony and data
presented to your Commission in 1905 and 1906, at the time
of the application of The City of New York for the approval

46

of the original map, plan and profile, dated October 9, 1905,
which map, plan and profile, with certain immaterial excep-
tions, was approved by your Board May 14, 1906.

Respectfully,

THOS. HASSETT,

Secretary.

47
BEFORE THE STATE WATER SUPPLY COMMISSION

In the Matter

of

The application of The City of New York to the
State Water Supply Commission for the ap-
proval of the report of the Board of Water Sup-
ply of The City of New York to the Board of
Estimate and Apportionment of The City of New'
York, dated November 15, 1909, recommending ^ Petition
modification of the map, plan and profile dated]
October 9, 1905, approved by said Commission'
May 14, 1906, which modification is dated No-
vember 15, 1909, and is entitled " Board of Wa-
ter Supply of The City of New York. Map and
profile showing manner of delivering the water
to the several Boroughs."

To the State Water Supply Commission-

The City of New York hereby respectfully makes applica-
tion by petition in writing to the State Water Supply Commis-
sion, pursuant to the provisions of Chapter 724 of the Laws
of 1905 and the acts amendatory thereof and supplemental
thereto, and of Chapter 56 of the Laws of 1909, being Chap-
ter 54 of the Consolidated Laws, and shows as follows:

1. The City of New York is a municipal corporation or-
ganized and existing in the State of New York by virtue of
its ancient charters and the Laws of the Colony of New York
and the Laws of the State of New York.

2. Pursuant to Chapter 724 of the Laws of 1905, and on
or about June 9, 1905, the Mayor of The City of New York
appointed J. Edward Simmons, Charles N. Chadwick and
Charles A. Shaw to be a Board or Commission to be called
Board of Water Supply of The City of New York. The said
Commissioners duly qualified and entered upon the perform-
ance of their duties on or about the said date and have since
continued to hold their said offices and to perform the duties
thereof, except that on January 28, 1908, the said J. Edward

48

Simmons resigned his said office and on January 30, 1908,
John A. Bensel was appointed by said Mayor to act as such
Commissioner, and on January 31, 1908, said John A. Bensel
duly qualified and entered upon the discharge of his duties
and has ever since continued to hold said office and perform
the duties thereof.

3. The Board of Water Supply proceeded pursuant to said
statutes and made such surveys, maps, plans, specifications,
estimates and investigations as they deemed proper in order
to ascertain the facts as to what sources for an additional
supply of pure and wholesome water for The City of New
York exist and are most available, desirable and best for the
said City, and under date of November 15, 1909, reported to
the Board of Estimate and Apportionment of The City of
New York recommending the delivery of the water to the
several boroughs of said City. A copy of said report is hereto
annexed marked "A," and is made a part of this petition. Ac-
companying said report was a map, plan and profile dated
November 15, 1909, entitled " Board of Water Supply of The
City of New York. Map and profile showing manner of de-
livering the water to the several boroughs." Said map, plan
and profile was duly signed by said Commissioners and their
engineers. Said map, plan and profile and the other papers
and documents accompanying this application form an exhibit
of maps of lands to be acquired and profiles thereof showing
the sites and areas of the proposed reservoirs and other works,
the profiles of the aqueduct lines and the flow lines of the
water when impounded, also plans and surveys and abstracts
of official reports relating to the same, showing the need of
The City of New York for the delivery of the Catskill water
to the several boroughs of said City and the reasons therefor.
This petition is accompanied by proof as to the character and
purity of the water supply proposed to be acquired and de-
livered.

4. The Board of Estimate and Apportionment, upon the
receipt of said report, map, plan and profile and prior to the
adoption thereof, did afford to all persons interested a reason-
able opportunity to be heard respecting the same and did give
reasonable public notice of such hearing whereat testimony
might be produced by the parties appearing in such manner as

49

the Board of Estimate and Apportionment might determine.
On November 19, 1909, the Board of Estimate and Appor-
tionment adopted a resolution in the following terms:

" Whereas, The Board of Water Supply of The City
of New York, pursuant to Chapter 724 of the Laws of
1905, as amended, has submitted to the Board of Estimate
and Apportionment a report and plan which bears the
date of November 15, 1909, and is entitled ' Map and
profile showing manner of delivering the water to the
several boroughs/ said map being now on file in the office
of the Board of Water Supply of The City of New York,
No. 299 Broadway, New York City; now therefore be it
" Resolved, That the 3rd day of December, 1909, at
10.30 o'clock in the forenoon, at Room 16, in the City
Hall, in The City of New York, be fixed as the time and
place for a public hearing upon the said report and plans,
and that notice be given of such public hearing by publica-
tion in the City Record, and in the newspapers designated
by the Board of City Record as official City papers ; and
be it further .

" Resolved, That the Secretary of this Board be di-
rected to give such notices as are provided for in said
statute."
5. Pursuant to the terms of said resolution a notice of
said public hearing on December 3, 1909, was duly published
in the City Record, and in the Sun, Times, Globe, Evening
Mail, Democracy, Tammany Times and Staats-Zeitung, being
the newspapers designated by the Board of City Record as
official City papers. Notice of said public hearing on Decem-
ber 3, 1909, was also duly given pursuant to the provisions of
Section 3 of Chapter 724 of the Laws of 1905, as amended, by
mailing to the President of the Board of Aldermen of The
City of New York, and to the City Clerk of The City of New
York, in behalf of the counties of New York, Kings, Queens
and Richmond, where real estate to be acquired is situated,
a notice of such hearing at least eight days before the time
named in said notice, there being no Board of Supervisors in
any of said four counties designated as such ; and by mailing
such notice to the Chairman and Clerk of the Board of Super-
visors of Westchester County at least eight days before De-

50

cember 3, 1909. All of said facts will more fully appear from
the records on file in the office of the Secretary of the said
Board of Estimate and Apportionment, all of which the peti-
tioner herein begs leave to refer to and to produce.

6. Said hearing before the Board of Estimate and Appor-
tionment was duly had on December 3, 1909, at 10.30 o'clock
in the forenoon, at Room 16, in the City Hall, Borough of
Manhattan, City of New York, being the time and place duly
set therefor, and was duly adjourned to December 10, 1909.
At said hearing the Board of Estimate and Apportionment
heard all who appeared in opposition to the approval of the
said report, map, plan and profile, and all who appeared in
favor thereof. On December 10, 1909, after due deliberation
said Board of Estimate and Apportionment duly adopted a
resolution approving and adopting the said report, map, plan
and profile. Said resolution is as follows:

" Whereas, The Board of Water Supply of The City
of New York, pursuant to Chapter 724 of the Laws of
1905, as amended, has made such surveys, maps, plans,
specifications, estimates and investigations as it deemed
proper, in order to ascertain the facts as to what sources
for an additional supply of pure and wholesome water
for The City of New York exist and are most available,
desirable and best for the said supply, and

" Whereas, The Board of Water Supply has reported
to the Board of Estimate and Apportionment under date
of November 15, 1909, recommending the approval of a
map, plan and profile dated November 15, 1909, and en-
titled : ' Board of Water Supply of The City of New
York. Catskill Aqueduct. Map and profile showing man-
ner of delivering the water to the several boroughs/ and
" Whereas, The Board of Estimate and Apportion-
ment upon the receipt of said report and the said map,
plan and profile, and on November 19, 1909, adopted a
resolution that December 3, 1909, at 10.30 o'clock in the
forenoon, at Room 16 in the City Hall, in The City of
New York, be fixed as the time and place for a public
hearing upon the said report, map, plan and profile, and
that notice be given of such public hearing by publication
in the City Record and in the newspapers designated by

51

the Board of City Record as official City papers, and that
the Secretary of the Board of Estimate and Apportion-
ment give such notices as are provided for in said statute,
and

" Whereas, The Board of Estimate and Apportion-
ment, in order to afford to all persons interested a reason-
able opportunity to be heard respecting the said report,
map, plan and profile, has given reasonable public notice
of such hearing, and, in addition, has given notice of such
hearing by mailing to the President of the Board of Al-
dermen of The City of New York and to the City Clerk
of The City of New York, in behalf of the Counties of
New York, Kings, Queens and Richmond, in which real
estate to be acquired is situated, a notice of such hearing
at least eight days before December 3, 1909, there being
no Boards of Supervisors designated as such in any of
said counties, and

" Whereas, Notice of such hearing was mailed to the
Chairman and the Clerk of the Board of Supervisors of
Westchester County, at least eight days before December
3rd, 1909, and

" Whereas, The said notice of said hearing was pub-
lished in all of the papers specified and referred to above,
being the City Record, and The Sun, The New York
Times, The Globe, The Evening Mail, Democracy, Tam-
many Times and Staats-Zeitung, the newspapers desig-
nated by the Board of City Record as official City papers,
all of which is evidenced by the affidavits, certificate*
and documents filed in the office of the Secretary of the
Board of Estimate and Apportionment, and

" Whereas, On December 3, 1909, at 10.30 o'clock in
the forenoon, in Room 16, in the City Hall, in The City
of New York, the Board of Estimate and Apportionment
met pursuant to said notice and a public hearing was
given to all persons interested, and a reasonable oppor-
tunity to be heard respecting the said report, map, plan
and profile was afforded to such persons, at which hearing
said report, map, plan and profile were considered and
due deliberation was had,

52

" Now, Therefore, be it

" Resolved, That the Board of Estimate and Apportion-
ment hereby approves and adopts the said report and map,
plan and profile, both dated November 15, 1909, and
hereby directs that the said map, plan and profile be
executed, signed, certified and filed as directed in Sec-
tion 3 of Chapter 724 of the Laws of 1905, as amended,
and hereby declares the same to be the final map, plan or
plans and profile approved and adopted by the Board of
Estimate and Apportionment as provided for in said sec-
tion; and be it further

" Resolved, That an application be made by petition
in writing to the State Water Supply Commission as
speedily as possible for the approval of said report, map,
plan and profile, pursuant to Chapter 56 of the Laws of
1909, being Chapter 54 of the Consolidated Laws known
as the ' State Boards and Commissions Law ' and that
the Corporation Counsel is hereby requested to prepare
such papers and to take such steps with that end in view
as may be proper."
7. After the approval and adoption of said report, map,
plan and profile, the said map was duly executed in quadrupli-
cate. One thereof accompanies this petition and is intended
to be filed herewith and made a part hereof. A second re-
mains on file with the Clerk of the Board of Estimate and
Apportionment. A third is placed on file in the office of the
Board of Water Supply. A fourth is filed in the office of the
Commissioner of Water Supply, Gas and Electricity of the
City of New York. A certified copy of said map is filed in
the office of the County Clerk or Register of each of the
counties in which the real estate affected thereby is situated.
A copy of the said report of the Board of Water Supply of
The City of New York to the Board of Estimate and Appor-
tionment, dated November 15, 1909, is also herewith presented,
together with an abstract of official reports relating to the
manner of delivering the water to the several boroughs of
The City of New York, and showing the need for the deliv-
ery of such water to The City of New York and the reasons
therefor. In addition, The City of New York herewith pre-
sents a plan or scheme to determine and provide for the pay-

53

ment of the proper compensation for any and all damages to
persons and property, whether direct or indirect, which will
result from the acquiring of said lands and the execution of
said plans. All of said matters will be more fully shown in
the proceedings, papers and documents which will be produced
at the hearing before the State Water Supply Commission.

8. The proposed delivery of such water to the said sev-
eral boroughs and the execution of the plans herewith presented
are justified by public necessity and are just and equitable
to the other municipalities and civil divisions of the State
affected thereby and to the inhabitants thereof, particular con-
sideration being given to their present and future necessities
for sources of water supply.

9. The plan or scheme to determine and provide for the
payment of proper compensation for any and all damages to
persons or property, whether direct or indirect, which will
result from the acquiring of the said lands and the execution
of the said plans, is to purchase the said lands and to secure
conveyances and releases thereof if the amount can be agreed
upon, and if not to acquire the same by condemnation proceed-
ings, as provided in Chapter 724 of the Laws of 1905 and the
acts amendatory thereof and supplemental thereto. The City
of New York is of abundant financial responsibility to pay
any and all of the aforesaid damages. It is proposed to pay
all such claims from the proceeds of Corporate Stock to be
issued from time to time by the Comptroller when thereto
authorized by the Board of Estimate and Apportionment.

Wherefore The City of New York hereby makes applica-
tion by petition in writing to the State Water Supply Com-
mission for the approval of the said report, map, plan and
profile, and has caused this petition to be subscribed by its
Mayor and by its City Clerk and its seal to be affixed hereto
this 15th day of December, 1909.

GEORGE B. McCLELLAN,
[l. s.] Mayor.

P. J. SCULLY,

City Clerk.
FRANCIS K. PENDLETON,

Corporation Counsel.

54

State of New York
County of New York
City of New York

► ss. .*

On the 15th day of December, in the year 1909, before
me personally came P. J. Scully, with whom I am personally
acquainted, and who is known to me to be the City Clerk of
The City of New York, who being by me duly sworn did de-
pose and say:

I reside in the Borough of Manhattan, City of New York.
I am City Clerk of The City of New York, the corporation
described in and which executed the foregoing petition. I
know the seal of said corporation. The seal affixed to said
petition is such corporate seal. It was thereto affixed by due
authority of said corporation, and I signed my name thereto
as City Clerk by like authority. I know George B. McClellan
and know him to be the person described in and who as
Mayor of The City of New York executed said petition. I
saw him subscribe and execute the same, and he acknowledged
to me, the said P. J. Scully, that he executed and delivered
the same, and I thereupon subscribed my name thereto.

CHAS. A. GLASER,

Commissioner of Deeds,

New York City.

55

State of New York,

State Water Supply Commission.

In the Matter

of \ Public Notice.

the Application of The City of New York.

Notice is hereby given that, pursuant to the provisions of
Chapter 724 of the Laws of 1905 and the acts amendatory
thereof and supplemental thereto, and to Article 2 of the State
Boards and Commissions Law, being Chapter 56 of the Laws
of 1909, the State Water Supply Commission will meet at
the office of the Board of Water Supply, No. 299 Broadway,
in the Borough of Manhattan, City of New York, on the 12th
day of January, 1910, at 11 o'clock in the forenoon of that
day for the purpose of hearing all persons, municipal cor-
porations or other civil divisions of the State of New York
that may be affected by the execution of the modification, or
amendment, dated November 15, 1909, of the plans of The
City of New York for securing a new and additional supply
of water, plans for which modification or amendment have
been filed with the New York State Water Supply Commis-
sion, at its office, Lyon Block, Albany, N. Y., where the same
are open for public inspection; and for the purpose of deter-
mining whether said plans are justified by public necessity
and whether the same are just and equitable to the other mu-
nicipalities and civil divisions of the State of New York and
to the inhabitants thereof affected thereby, and whether said
plans make fair and equitable provisions for the determination
and payment of any and all damages to persons and property,
both direct and indirect, which will result from the execu-
tion thereof.

The execution of such plans, it is alleged, will affect lands
situate in the Counties of New York, Kings, Queens and Rich-
mond.

All persons, municipal corporations and other civil divisions
of the State of New York who have objection to the execu-
tion of said plans, in order to be heard thereon, must file such

56

objections thereto in writing in the office of the State Water
Supply Commission in the city of Albany, N. Y., on or before
the 11th day of January, 1910. Every objection so filed must
particularly specify the grounds thereof.

No person, municipal corporation or local authority can
be heard in opposition thereto except on objections so filed.

Dated, Albany, N. Y., December 16, 1909.

HENRY H. PERSONS,

President.
ERNST J. LEDERLE,
MILO M. ACKER,
JOHN A. SLEICHER,
CHARLES DAVIS,

State Water Supply Commission.

57

BOARD OF ESTIMATE AND APPORTIONMENT

CITY OF NEW YORK

OFFICE OF THE SECRETARY

277 BROADWAY

New York, January 7, 1910.

Mr. Thomas Hassett, Secretary,
Board of Water Supply,
299 Broadway,

New York City.
Dear Sir:

I transmit herewith certified copy of a resolution adopted
by the Board of Estimate and Apportionment at the meeting
held this day, requesting the State Water Supply Commission
to defer final action upon any projected extensions or modifi-
cations of New York's Water Supply System.

I am informed that the State Board will, on January 12,
1910, consider the plan of Water Supply Extension in the
County of Suffolk, adopted by the Board of Estimate and
Apportionment on June 26, 1908, and the plan of the Water
Supply Pressure Tunnel under the Borough of Manhattan,
adopted by the Board of Estimate and Apportionment on De-
cember 10, 1909.

Respectfully,

JOSEPH HAAG,

Secretary.

Whereas, The Board of Estimate and Apportionment on
June 26, 1908, approved of a plan of water supply extension
in the County of Suffolk, and under date of December 10,
1909, approved of a water supply pressure tunnel under the
Borough of Manhattan, both of which matters are under the
jurisdiction of the Board of Water Supply and are now under
consideration by the State Water Supply Commission.

Resolved, That the Board of Estimate and Apportionment
request the State Water Supply Commission to defer final
action upon any projected extensions or modifications of New
York's Water Supply System.

I hereby certify that the foregoing is a true copy of a reso-
lution adopted by the Board of Estimate and Apportionment
of The City of New York at a meeting of said Board held
on January 7, 1910.

JOSEPH HAAG,

Secretary.

58

BOARD OF ESTIMATE AND APPORTIONMENT

CITY OF NEW YORK

OFFICE OF THE SECRETARY

277 BROADWAY

March 4, 1910.
Thomas H. Keogh, Esq.,

Secretary, Board of Water Supply,

299 Broadway, New York City.
Dear Sir:

I transmit herewith certified copy of resolution adopted
by the Bbard of Estimate and Apportionment March 4, 1910,
providing for the appointment of a Committee of three, w T ith
instructions to retain as expert advisers two engineers and
a geologist, on the matter of the construction of a pressure
tunnel under Manhattan Island from Hill View reservoir to
the Bofough of Brooklyn, and to report thereon to said Board
at the earliest possible moment.

In accordance with the provisions of the resolution the
Mayor appointed the President of the Board of Aldermen, the
Comptroller and the President of the Borough of Manhattan
as members of the Committee.

Respectfully,

JOSEPH HAAG,

Secretary.

59

BOARD OF ESTIMATE AND APPORTIONMENT

CITY OF NEW YORK

Whereas, the former Board of Estimate and Apportion-
ment did on December 10, 1909, authorize a modification of
the general plan of the Board of Water Supply contemplating
the construction of a pressure tunnel under Manhattan Island
from Hill View reservoir to the Borough of Brooklyn, and

Whereas, the present Board of Estimate and Apportion-
ment did by resolution introduced on January 7, 1910, request
the State Board of Water Supply to suspend action for ap-
proval of this modification until an opportunity had been had
for examination into the merits of the plan; now, therefore,
be it

Resolved, That a committee of three be appointed with
instructions to retain as expert advisers two engineers and a
geologist, and that the committee be instructed to examine
into the engineering feasibility of the proposed pressure tun-
nel and to report !hereon at the earliest possible moment to
this Board.

I hereby certify that the foregoing is a true copy of a reso-
lution adopted by the Board of Estimate and Apportionment
at the meeting of sar'd Board, held on the 4th day of March,
1910.

JOSEPH HAAG,

Secretary.

60

REPORT ON DISTRIBUTION OF CATSKILL WATER

SUPPLY IN NEW YORK CITY

Hon. Wm. A. Prendergast, Hon. John Purroy Mitchel

and Hon. George McAneny, Committee of the Board

of Estimate and Apportionment of The

City of New York.

Gentlemen — The undersigned, acting by reason of your
letters to them of March 25 and 28, 1910, respectfully report:

In answer to the first question asked us, namely : " Is the
proposed Manhattan tunnel practicable, from an engineering
and geological standpoint/' we say as follows:

Practicability — Manhattan Pressure Tunnel

The proposed Manhattan tunnel is to be a " pressure
tunnel," running from the proposed Hill View reservoir,
located at the downstream end of the Catskill water supply
conduit now under construction and about half completed,
thence passing under the westerly part of the middle of Man-
hattan Island, and thence across to Brooklyn. Its route has
been thus selected so as to cause the tunnel to pass through
a territory promising, for geological reasons, to be the best
that can be found between the end points described. In carry-
ing capacity it is gradually to diminish from Hill View to
Brooklyn.

A " pressure tunnel," which is thus designated on account
of its being designed to convey water under pressure, must be
placed, as usually constructed, at such a depth below the sur-
face of the ground, that the weight per square foot of the
overlying material is at least equal to the pressure per square
foot upwards of the contained water.

Such a location, as regards depth below the surface, places
no reliance on the strength, or resistance to rupture, of the
surrounding ledge-rock, and is therefore conservatively safe.

In the present instance this method of construction places
the tunnel about 200 feet below the street level, but for pur-
poses of crossing in good rock, under the Harlem river, Man-
hattanville valley and the East river, this depth is increased to
about 350 feet and to not less than about 600 feet respectively,
kept elsewhere at not less than 150 feet beneath the "rock
floor."

61

Borings, Making and Completed

To explore the nature of the ground, and when necessary
to find lower down the rock floor referred to, bore holes have
been put down, since December, 1908, all along the line de-
scribed. This line passes under streets, parks and other prop-
erty of the City, some eighteen miles, with the exception only
of about a quarter of a mile of right of way to be acquired.
One hundred and twenty-five such bore holes have been com-
pleted, and at least thirty more have been begun, or are
planned, extending in many cases to the proposed tunnel
grade. This will give indications of the nature of the ground
to be met with in tunneling, much more complete and instruc-
tive than formed the basis of the location of other pressure
tunnels that have been built in years past. It should be remem-
bered in this connection that the art of making borings and
of extracting core specimens of rock penetrated is constantly
advancing, no less than other arts. No such knowledge before-
hand of conditions to be encountered, as is now available, was
at hand, for instance, for the builders of the Harlem River
crossing of the new Croton Aqueduct pressure tunnel built
twenty years ago. Nor for the construction of certain other
such tunnels, built since that time.

Available Data

We have carefully studied the geological data thus and
otherwise made available, including the experiences had in
other tunneling operations in this vicinity, such as the con-
struction of the Harlem River pressure tunnel, built in 1885-
1891, just mentioned; the Pennsylvania Railroad tunnels, lately
completed ; the Webster Avenue sewer, running to the Harlem
river; the Bronx Valley storm relief sewer, now under con-
struction ; the Rondout, Wallkill and Moodna pressure tunnels,
forming a part of the new Catskill water supply, two of them
built at a level of 200 feet below sea level, which we have
personally examined , the Steinway tunnel and the East River
gas tunnel ; the Battery tunnel to Brooklyn, and certain shafts
put down in Manhattan borough.

We have gone over the whole length of the line described,
from the East river to Hill View, and have examined rock

62

cores or specimens brought up in the making of the bore holes
named, which are preserved for future use in the letting of the
construction contracts, at the 92nd Street gate-house. We have
also studied, up to date, the weekly reports made concerning
the bore holes now being put down.

Geological Conclusions

From a detailed examination of all the geological data
accessible, we are of opinion that the construction of a pressure
tunnel along the line laid down on the plans of the Board of
Water Supply, and its subsequent maintenance, are entirely
practicable. Keeping in mind the geology of the district to
be traversed, which we regard as unusually well explored,
it seems unlikely that such seams, soft spots, loose pockets,
faults or zones of crushing or of deep decay should be met,
even for short distances, as will render impracticable the
proper construction of the tunnel at the depths proposed ; and
it does not appear at this writing probable even that such con-
ditions will be met, as will require any material change from
the present plans of the Board of Water Supply, with the
possible exceptions noted below.

Concerning a short distance across the lower east side of
Manhattan, from the corner of Spring street and the Bowery
to the river front at Clinton street, the geological data are
still incomplete. From the condition of the deep rock, as shown
by gross and microscopic examination of rock cores from this
field, we are convinced that this section also is a practicable
route substantially as proposed; but final judgment must be
deferred upon the depth and character of the tunnel, the cost
and upon the time required for the construction of the shafts
and tunnels in this section, pending the completion of the bor-
ing operations conducted by the Board of Water Supply. The
same may be said concerning the line for a distance of about
1,000 feet on 106th street. Detailed geological data upon
which these deductions are based are discussed in Appendices
A. B and C.

Other Pressure Tunnels in the United States

Pressure tunnels, so far as we are informed, had their be-
ginning in the United States right here in New York, the

63

Harlem River crossing of the new Croton aqueduct, 1885-
1891, being the first pressure tunnel built, so far as we know ;
seven miles long, and containing a pressure of 103 feet of
water (about 45 pounds per square inch).

The accomplished Chief Engineer of this work, the late
Mr. A. Fteley, on page 87 of his report dated January 1, 1895,
says this concerning the Harlem River crossing tunnel : " This
feature, that is, the construction of the aqueduct for seven
miles, under pressure, is a bold innovation."

However the point of priority may be decided, true it is
that the Harlem River pressure tunnel has been in every way
a complete success for the twenty years of its existence in
service ; and others have not hesitated to profit by its example.

Thus there is a pressure tunnel under the City of Wash-
ington, put into service in 1898, after it had lain defective,
unfinished and idle for a period of nigh ten years, 4 miles
long, and carrying a pressure of 123 feet of water (53 pounds
per square inch). One thousand feet of it, where it passes
under Rock creek, is lined with cast-iron rings. The Board
of Engineers, who reported in 1896 recommending the comple-
tion of the tunnel, were divided in opinion whether the safe
transit of these 1,000 feet under the Rock Creek valley should
be made by going deeper and into sound rock for that length
or by lining the tunnel, some 9 feet in diameter, with cast-iron
rings. The lining method was adopted, and there is no doubt
that the other method would have given equally good results.

The history of both pressure tunnels and of conduits not
under pressure built by tunneling methods (and much such his-
tory has been written in the United States in the past twenty-five
years) plainly teaches what are the essentials of good design,
and also the necessity on the part of the supervising engineer
to see to it that the conditions of the specifications be carried
out during construction.

There can no longer be any doubt that good design as well
as faithful performance of the specifications can now be
secured.

Pressure tunnels carrying 60, 37 and 21 feet of water
pressure are in service at Cincinnati, Kansas City and Phila-
delphia, built between 1900 and 1906; and many others, built
so as to run full of water, but carrying no unbalanced pressure,

64

are in use in the United States. The Cincinnati tunnel is
noted for having been constructed in the face of a greater
than the usually found quantity of inflow of water, due to
the seamy, soft yellow limestone of the Ohio valley through
which this tunnel passes.

An instructive example of the practicabilities of such struc-
tures, even when at first of defective design, is given by the
pressure tunnel, in effect the penstock or pipe carrying the
power water, to the Kern River hydro-electric plant of the
Southern California Edison Company, of Los Angeles, Cali-
fornia. Parts of this tunnel act under a pressure of about
870 feet (about 380 pounds per square inch), about double
the pressure put on a modern high pressure steam boiler.

This tunnel, as first completed in 1907, had no proper
location or lining to resist either internal or external pressure.
Nevertheless, by the skillful design and thorough work of the
present Vice-President and General Manager, it has been
restored to its intended usefulness, and has been in service
since September 1, 1909.

The many acres of ledge rock, honeycombed with tunnels
which were placed with their roof within some 20 feet of the
bottom of the river and used in the removal of obstructions
to navigation at Hell Gate, in the East river, form another
well known illustration in this vicinity of practicable tunneling
carried on in submerged rock, close to and directly under the
river.

Opinion

An unusually complete collection of geological data and
the results of borings already made thus make it highly proba-
ble that none but the ordinary difficulties of plain tunneling
will be met with in the construction of the proposed Manhattan
pressure tunnel; and the experience had in the construction
of other pressure tunnels in this vicinity and elsewhere in the
United States during the past twenty-five years change this
probability into a certainty that the proposed pressure tunnel
is practicable. Whatever bad ground may be revealed by the
actual work of tunnel building, which the borings made and
yet to be made have not revealed, can be passed through,
over, under or around by methods that have been used in the
like cases elsewhere and at no extraordinary cost.

65

We therefore answer in the affirmative your first question :
" Is the proposed Manhattan tunnel practicable from an engi-
neering and geological standpoint?"

Comparative Projects

Your second question is : " How does the estimated and
probable cost of this tunnel compare with (a) the estimated
and probable cost of a pipe line from Hill View reservoir
through Queens to the Borough of Manhattan, and (b) a
pressure tunnel from Hill View through Queens to Brooklyn ?"

The question is intended, we assume, to call for compari-
sons of cost on the routes and of the kinds of water conduits
described, when built of equal water and pressure carrying
capacity, and serving an equal area of distribution, as other-
wise a comparison could not be made.

The proposed Manhattan pressure tunnel, like the Catskill
aqueduct, now building, is to carry at its upstream end a supply
of 500 million gallons daily ; and passing, in gradually dimin-
ishing sizes, to Brooklyn through the Boroughs of The Bronx
and Manhattan, will supply the distribution systems of these
three Boroughs at a pressure, where desired, of about 100 feet
(43 pounds per square inch) greater than at present; and by
pipe-line extensions it will also thus supply the Boroughs of
Queens and Richmond; that is: at pressures, where desired,
of about 275 feet in The Bronx ; 280 feet in Manhattan ; 245
feet in Queens; and 225 feet in Richmond; while any conduit
built on the line direct from Hill View through Queens to
Brooklyn will necessarily demand other and additional con-
duits also to supply Manhattan Island.

Increased Pressure When Desired

We cannot assume that no portion of the Catskill water-
supply will at no time be needed in the Borough of Manhattan.
We believe, on the contrary, that its delivery under the in-
creased pressure, nearly 100 feet (43 pounds per square inch)
of increased pressure, which the proposed Manhattan pressure
tunnel would furnish, would be of very great value to the
Borough of Manhattan to-day, and for all time, in giving
eventually the chief city of the United States a pressure in its
supply for fire and domestic purposes such as is customary in

66

other cities and in villages of the United States, and in reliev-
ing the city from a very great daily expense of pumping water
those same 100 feet at high service City pumping-stations and
also at thousands of privately owned pumping engine plants
of all kinds located in dwellings and other buildings.

The Manhattan pressure tunnel is designed to deliver water
at many uptake shafts, placed at intervals of about 4,000 feet
throughout its length of nearly eighteen miles, at any locally
desired pressure (up to its limit of action), by means of
pressure regulators, so that no fear of an undue overloading
of the strength of the street mains or of plumbing need be
entertained. Water pressure in cities has money value and is
sought for and quickly utilized whenever available. In the
course of years all fixtures are, when necessary, rebuilt to suit
the increased pressure, and meantime any district or single
buildings within any district may be kept supplied at the former
pressure, if so desired, by the use of the simple and inexpen-
sive appliance known as a pressure regulator. . It is thus made
practicably expedient to introduce the more desirable and valu-
able street main pressure gradually and as it may be called for
by the water consumers. As reducing insurance rates alone,
such increased pressure is palpably of very great value.

Pumping to Be Dispensed With

The present high service pumping above mentioned amounts
to about 75 million gallons daily in Manhattan, 25 million
gallons in Brooklyn and 30 million gallons by the pumps of
citizens, 130 million gallons daily in all, costing at the City
pumping-stations about $400,000 annually ; at the private pump-
ing plants a sum difficult to estimate, but by careful inquiry
and conservative estimate this has been found to amount to
not less than the great sum of $1,400,000 annually, a total of
$1,800,000 annually, when the estimates were made, which in
a few years will certainly amount to at least $2,000,000 annu-
ally, representing a capital of some $50,000,000.

Brooklyn Pumping Wholly to Be Dispensed With for a

Time

Nor do even these estimates represent all possible saving
in expenses now incurred for pumping. As is well known

67

to the Department of Water Supply, Gas and Electricity, all
the pumping-stations in the Borough of Brooklyn, both low
service and high service, the two now costing for operation
about $1,000,000 annually, without counting renewal fund and
repairs, could be advantageously shut down for ten years if the
Brooklyn distribution system could take its supply of water
from the proposed Manhattan pressure tunnel/

Over $200,000 annually is also spent in Brooklyn in the
purchase of water from private water companies, which may
also be saved.

It is well known that a thorough repair, in most cases
a rearrangement, of the Brooklyn pumping-station machinery
would quickly pay for itself in a saving of undue cost of oper-
ation ; but this has not been and is not now possible on account
of the constant great overload and strain to which these works
have been and are subjected. To give opportunity, therefore,
for a rearrangement or for the rehabilitating of the pumping-
stations of Brooklyn would be not the least of the valuable
services which the proposed Manhattan pressure tunnel would
give to the interests of the City.

Consumption of Catskill Water in Manhattan

Returning to the consideration of the idea not to allow any
of the Catskill water-supply ever to be distributed in Man-
hattan island, we find that within about thirty years no less
than 180 millon gallons daily of this supply will be needed in
the Borough of Manhattan, even if the whole of the Croton
water-supply be reserved in addition and for Manhattan ex-
clusively, which shows that a conduit of some sort from Hill
View to Manhattan must be constructed.

Cross-Connection, Manhattan-Brooklyn

Nor can we assume that there is no value in a cross-connec-
tion of great carrying capacity between Manhattan and
Brooklyn. We believe, on the contrary, that a cross-connection
between these two boroughs and their main distribution reser-
voirs, such as the Manhattan pressure tunnel would create,
will for all time be of great value in the safe and prudent
operation of the water-supply of the great City of New York,

68

and should be acquired as soon as this may expediently be
done. To be most effective it should connect by properly
dimensioned conduits the Central Park and Brooklyn reser-
voirs.

Parallel Lines of Water Mains

Even then the two plans referred to could not be compared
merely on the basis of first cost. A pressure tunnel has prac-
tically no maintenance charges, while pipe-lines are subject
to accidental breakage, if of cast iron, and to comparatively
great renewal charges if of steel. Especially objectionable are
parallel lines of such large pipes laid closely together, as the\
would have to be laid in city streets. Mr. A. Fteley, Chief
Engineer of the New Croton aqueduct, felt so strongly on this
subject that he recorded his objections to the eight 48-inch
pipe-lines laid in Convent avenue (page 88 of his Report,
dated January 1, 1895), even after these pipes had been long
laid and in service. Should one such pipe of a parallel row
of pipes break there is always danger of its undermining its
neighbors, until all the pipes are broken.

There is also to be considered the advantages to the City
in having work go on in tunnels, under cover, and without
annoyance to street traffic of all kinds, rather than undertake
to lay large water pipes in streets already excessively encum-
bered with underground pipes, conduits, sewers, subways and
other subsurface structures, with more to come, and with an
ever increasing street traffic to be served at all times.

First Cost Comparisons

But barring those accompanying advantages of the pressure
tunnel plan whose money values cannot be readily computed,
our comparisons must be made between the first cost of the
proposed Manhattan pressure tunnel and the first cost (a) of
a pipe-line from Hill View reservoir through Queens to the
Borough of Brooklyn, supplemented by a pipe-line from Hill
View to Manhattan, together with a cross-connection direct
between Brooklyn and Manhattan, all of this of equal carry-
ing capacity and distributing capacity to the Manhattan pres-
sure tunnel first named ; also (b) between the first cost of the
proposed Manhattan pressure tunnel and the first cost of a

69

•

pressure tunnel substituted for the pipe-lines just described
under letter (a), this last being a comparison of first cost
between two pressure tunnels built on two different routes.

This Queens and Brooklyn pressure tunnel must, for pur-
poses of enabling a comparison to be made, be supplemented
(as was the pipe-line) by a good and sufficient pipe-line from
Hill View to Manhattan, and by a proper direct cross-connec-
tion, Brooklyn to Manhattan.

Comparing now our estimated probable first cost and time
necessary for completion of the Manhattan pressure tunnel,
with the estimated probable first cost and time necessary for
completion of an equivalent pipe-line (your question 2, under
letter a) we find that the Manhattan pressure tunnel will cost
about $26,000,000, and will require about four and one-quarter
years to construct, while an equivalent pipe-line system will
cost about $47,000,000 and will require about four and one-
half years to construct; a saving of first cost of a pressure
tunnel as compared with pipe-lines of $21,000,000. For details
of which statement reference is had to Appendices D, E, F
and G.

Route Comparison

Taking up our consideration of a comparison of the two
pressure tunnels, Hill View via Manhattan to Brooklyn, and
Hill View via Queens to Brooklyn (the subject outlined by
Question 2, b), we are met with the fact that no borings exist
on the Wards Island route. Consequently, over a year's time
would be lost on that line in exploring the subsurface. The
topography of this portion of the country shows a large and
broad area over which the rock floor is depressed below sea-
level ; and it is known that the zone of disturbed rock occupying
in general the valley of East river is broader here than further
south. A tunnel on this route would be obliged to cross more
rock contacts and traverse greater stretches of poor ground
than by the, route now proposed. These conditions argue strongly
against the practicability of this route; but on account of a
lack of detailed information as to the conditions to be encoun-
tered, a comparative estimate of the tunnel: Hill View via
Queens to Brooklyn, scheduled under Question 2, b, can hardly
be made.

70

We only know that with equally good ground to be met
with, the Manhattan .tunnel would cost less; being on a direct
and central line that is capable of supplying all the five Bor-
oughs; and not needing the supplements of a separate and
special line to supply Manhattan, and of a separate and special
cross-connection between Brooklyn and Manhattan.

Question 3

Our answer under Question 2, b, just stated, naturally
applies also to Question 3:

" Which in your opinion is the better route for a pressure
tunnel if constructed, (a) from Hill View reservoir, through
Queens to Brooklyn, or (b) from Hill View reservoir, through
Manhattan island to Brooklyn."

Conclusion

If we were tersely to sum up the considerations which are
not included in a mere comparison of first costs, as presented
by the three questions we have answered, and to emphasize the
value of the advantages which the proposed Manhattan
pressure tunnel will confer upon the City, such as increased
pressure gained (a very valuable item in the way of saving
fire insurance, and in saving pumping expenses, as already
shown), no encumbrances of streets during construction, nor
of their subsoil thereafter, and the like considerations, we
should say that The City of New York must have the Man-
hattan pressure tunnel to distribute the Catskill water-supply,
or its equivalent; and from the results of our studies, we find
that the Manhattan pressure tunnel may be constructed at
much less cost, with less annoyance and immediate danger
during construction, that it will be more valuable in use imme-
diately and in the future, and will cost much less to operate
and maintain.

Cost Estimate

The detailed estimates given in full in Appendix F, are based
on contractor's actual costs of similar work in New York
City, and prices on similar work adjusted to meet the restric-
tions of the City ordinances. They are conservative and it is
believed the contracts can be let well within these figures.

71

Estimated Time of Completion

In estimating the time of completion, see Appendix G,
for rock excavation in shaft and tunnel within City limits, the.
fact that blasting is not allowed between sunset and sunrise
was given full consideration.

Drilling in shafts in residential sections will in all proba-
bility not be permitted after 9 or 10 p. m. These conditions
taken in connection with the eight-hour labor law, will cut
down progress and enhance costs.

The progress assumed is based on actual performance of
similar work in New York City.

Other Distribution Plans Considered

An estimate was made of the cost of a pressure tunnel to
deliver 250 million gallons daily (see Appendix H), in
view of the possible saving in postponing the distribution of
the second 250 million gallons daily to some future time. The
cost of the smaller tunnel was found, however, to be 76 per
cent, of the cost of the 500 million gallons daily capacity
tunnel.

Building at Intervals

The cost estimates given in Appendices H and I, indi-
cate that a serious loss of money would be the result of
attempting to provide for the distribution of the Catskill
water-supply by installments of pressure tunnels or pipe-lines
built at intervals of time, and providing at each time for the
distribution of only a part of this supply.

Pipe Galleries

We have considered the suggestion that has been offered,
from time to time, these twenty years, that subways for pas-
senger travel, and 66-inch main conduits to convey water
placed under about 300 feet pressure, could economically and
with a proper degree of safety be carried in one and the
same tunnel excavation. We advise against that mode of
either subway or of water-supply construction, for reasons
which we assume we need not at this time give in detail.

72

The Chief Engineer of the Public Service Commission for
the First District of the State of New York writes us :

" The suggestion to use pipe galleries for steel pipe-lines
66 inches in diameter, carrying water under a pressure of 300
feet head, hardly seems feasible. These pipe lines would take
up practically the entire gallery, and I might also add that this
Department has found the difficulties in the construction of
pipe galleries in connection with subway work so great that
it considers them impracticable and hopes that they will ulti-
mately be abandoned.

" I would suggest that the proposed pipe-lines be laid in
streets where there are no subways, and that where they cross
the proposed subway lines the locations should be taken up in
detail with this Department, so that we can advise you as to
the proper depth of the pipe lines at the sites proposed. These
subway lines have not yet been designed, but I should be
pleased to make a special study for you at such points as may
be necessary."

Water Waste Prevention

One subject we have not yet touched upon is that of a
future restriction of water waste throughout The City of New
York, and whether it can be made to affect the conclusions we
have reached.

This is a subject the treatment of which borders on the
realms of prophecy.

If the government of the great City of New York
through a series of years were a simple matter, it might be
said, with some measure of certainty, what could and would
be accomplished during any stated period as regards water
waste prevention. But the course of future events in that line
will be governed by a very complex combination of circum-
stances.

Individually, we thoroughly believe in the work of water
waste prevention now conducted within the Department of
Water Supply, Gas and Electricity, by able men, appointed
with a view to having the desired results accomplished.

And doubt not that eventually waste will cease to run riot
as it has in the long past of New York City; its water con-
sumption attaining possibly the degree of good administration
and of thrift which has for thirty years been exhibited by

73

Providence, R. I., a city of some 200,000 population (about
60 gallons per day per capita), and for shorter periods of time
to an equal degree, or for the same length of time to a lesser
degree (from 60 to say 100 gallons per day per capita), by
many other American cities.

But this will not be accomplished without due and con-
tinued effort extending over years of time. Our inquiries on
this subject lead us to the belief, in agreement with competent
estimates that have been made, that to complete the work of
inaugurating a thorough curtailment of water waste in New
York City may, under favorable circumstances, require eight
years.

Meantime, whatever happens, a proper and sufficient supply
of water for fire and domestic purposes throughout The City
of New York must at all times be furnished, and it is the duty
of every one engaged in this incessant work, by the exercise ,
of forethought, to see that nowhere and at no time shall there
be an interruption to an adequate supply of water to the City,
so vitally important to its welfare. We do not believe that con-
siderations of an attainable reduction of water waste should
be allowed to affect any of the work of water-supply now in
progress or projected.

We have been greatly pleased — some of us have been agree-
ably surprised — at the extensive and able study that this project
of a Manhattan pressure tunnel has already received. Besides
replying to the specific questions put to us as we have done,
we desire again to say that, whether viewed from the point of
first cost, maintenance or of future cost, our opinion is that
The City of New York will do well to direct the immediate
construction of the proposed Manhattan pressure tunnel, for
purposes of distributing the Catskill water-supply to the five
Boroughs.

Respectfully submitted,

CLEMENS HERSCHEL,

Hydraulic Engineer.
FRANCIS L. PRUYN,

Consulting Engineer.
J. . EDMUND WOODMAN,

Mining Geologist.

No. 2 Wall street, New York, May 14, 1910.

74

APPENDIX A

GENERAL DISCUSSION OF THE GEOLOGICAL

PROBLEMS INVOLVED

Rocks Traversed by Proposed Line

At least five geological formations of different types are
found along the line of the tunnel.

(1) Glacial and recent accumulations; boulders, gravels,
clays, sand and river mud and silt ; all unconsolidated. These
will be met only in shafts.

(2) Manhattan schist, occupying most of Manhattan
Island; chiefly mica schist with occasional coarse features.

(3) In wood limestone, occupying certain lowlands. It is
essentially a coarsely crystalline magnesian variety when pure,
and becomes a schist with much mica when impure.

(4) Fordham gneiss, occupying much of The Bronx, and
parts of southeastern Manhattan and western Queens and
Brooklyn. It varies much from a fine schist to a coarse gneiss,
and has in places a granitic phase (really a separate intrusive
rock) called in subsequent pages a grano-diorite.

(5) Yonkers gneiss, found intrusive into the Fordham.
A coarse gneiss of great strength.

These are folded, sometimes violently, into a series of
north-northeast folds, that pitch more or less to the south.

General Description of Rocks Along Tunnel Line

Hill View reservoir is located in Yonkers gneiss. Thence
from a downtake shaft the pressure tunnel starts southward,
running approximately 8,400 feet in this rock. Passing to the
Fordham gneiss across a contact which surface field evidence
indicates will be sound, it traverses 21,190 feet of this rock
to the margin of Harlem river and a contact with Inwood lime-
stone. All this is under high land, in which numerous out-
crops serve but to add to the testimony of the drill holes as to
the soundness of the underlying rock. No cross-zones of deep
decay, fracturing or faulting are known.

75

The breadth of Inwdod limestone traversed under Harlem
river is about 820 feet, all sound. The contact on the west
side of the stream is between Inwood limestone and Manhattan
schist, and according to the evidence of the drill-holes is
thoroughly tight and 'firm.

From the crossing above mentioned, to approximately the
corner of the Bowery and Delancey street, the tunnel passes
uninterruptedly through this schist. The limestone of the
Harlem valley runs south to 108th street, just west of Central
park. West of this limestone the rock is schist and the land
is high. It has been the evident aim in locating the tunnel line
to run well within the latter, but to keep as far east as possible.
It should be made certain that the line does not now lie in a
contact zone, too close to the limestone.

At two points in the part of Manhattan now being dis-
cussed, cross valleys of weak rock have been encountered. One
of these, Manhattanville, while being topographically low and
showing deep glacial drift and deep decay in the bedrock
below, is now known to have sufficiently good rock at the
grade proposed for the tunnel at this point. But in order to
meet the conditions the grade was depressed slightly, from
338 feet to 386 feet.

At the second point, the northwest corner of Central park,
the tunnel turns along 106th street, from Columbus avenue,
making its first cross-traverse in the schist. The line has been
located so as to avoid most of the decay and disturbance; but
it is possible that this has not been fully accomplished. The
tunnel grade is raised to 153 feet under the worst part of the
district, the rise starting at 121st street, immediately south of
the Manhattanville disturbance. It seems certain that if the
lower grade (approximately 385 feet) be maintained until
Central Park is entered, or down to Shaft 12, good rock
will be reached.

When it is considered that a deep grade has already been
maintained from the Harlem River crossing to Morningside
park, the additional expense of this prolongation of the deep
grade will be almost negligible. The increase in security, on
the other hand, will be great.

In the course of thus depressing the tunnel grade along
106th street, limestone may be met with; since a reef of this

76

rock pitches gently southward here, having the surface at
108th street. As this would involve the crossing of two
more contacts and the traverse of a rock that should be avoided
wherever possible, it may be found advisable to change the
line slightly. Deeper holes along the latter will determine
whether this is necessary.

The distance in Manhattan schist north of Delancey street
is 49,860 feet.

The " lower east side section " is treated specifically in
Appendix C. It is sufficient to say here that the traverse
from the Bowery and Delancey street to the river at Clinton
street is in slightly unsound rock for parts of the distance and
it may be found advisable to depress the tunnel grade below
600 feet as at present located.

After entering Fordham gneiss unusually good rock is met
to the uptake shaft (No. 23) in Brooklyn.

Proportions of Different Rocks Encountered

The four main varieties of bedrock will require tunnelling
through approximately the following distances :

*

Feet

Yonkers gneiss 8,400

Fordham gneiss 33,650

Manhattan schist 49,680

Inwood limestone 2,200

Total 93,930

Of this only 4,800 feet are cross-traverse excavation, the
remaining being either on the strike of rocks or at a slight
angle from it.

II

An answer to the question " Is the proposed Manhattan
tunnel practicable from a geological standpoint ?"

Dangers to Pressure Tunnels Due to Rock Condition

Taking the definition of a pressure tunnel given on page 60,
it is evident that there are two classes of dangers that may be
met in constructing and maintaining such a tunnel :

1. During construction.

2. During maintenance and subsequent to construction.
The character of the rock must be such that neither of these

will be encountered to such degree as to endanger the structure,,
or the safety of human beings; nor on the other hand must
such dangers greatly extend the time of construction or unduly
augment the cost of construction or maintenance.
The dangers during construction are:

(a) Such inflow of ground-water or sea water, in amount
or suddenness or both, as will either flood that part of the
project or greatly increase its cost. With modern pumping
methods the amount of water that can be handled is very large,
before abandonment of ' an excavation becomes necessary. In
our judgment there is not the slightest probability, even in the
poorest ground thus far developed by boreholes, that abandon-
ment of any section of the tunnel project will be necessary.

(b) Another danger is the caving or even inflow of soft
material, so as to hinder or prevent work from being pushed
to the stage of constructing the permanent lining. This will
be considered below.

The dangers subsequent to construction are chiefly (1) out-
flow or leakage due to extreme porosity of the rock, which
may occur without much regard to the differential of pressure
between that exerted by the rock with its inclosed water and
the outward pressure of the tunnel water; (2) inflow and
mingling of water from without with that within the tunnel.
These are both due in part to defective lining, and it is believed
that the possibility of their occurrence can be neglected here,
constructional care being depended upon to eliminate them.

The sources of- danger from caving of material or from
inflow of water are several :

(1) Rock Naturally Porous — The only variety met in this
project that could be regarded as thus liable is the Inwood
limestone. Limestones, on account of solubility, are frequently
occupied by small or large cavities, ranging from almost
microscopic size to caves. The Inwood formation contains
so much magnesia as to be less easily soluble than most lime-
stones; and the boreholes have shown it to be compact, firm
and evenly crystalline — indeed, a superior rock when fresh.

78

(2) Contacts Between Rock Formations — Contacts be-
tween two dissimilar rocks are frequently weak, and it is not
rare to find in regions of intense folding, as New York is,
that slipping and other disturbances have taken place along
these planes, which have later acted as underground water
channels. Special attention appears to have been given this
matter in exploration; and it has been proved that in no case
is a contact per se likely to be a source of danger in the con-
struction of this tunnel. Wherever contacts or immediately
adjacent rock have been found in bad condition, there is seen
to be a special reason for that state.

(3) Fracture and Fault Zones — In some cases both frac-
tures and faults are tight enough to offer no trouble whatever
at such depths as are reached by this tunnel. In others they
are lines of subterranean water circulation to some extent. In
that instance they may cause inconvenience and perhaps in-
crease the cost of construction locally; but they do not com-
monly give such trouble as seriously to hinder work, unless
it be where the fault is itself a zone of broken rock.

In such instances (a) fracture may be largely self-healing,
plastic flow of the rock closing up all gaps. This is what has
happened in the disturbed rocks along the northern division of
the Catskill aqueduct, and is characteristic of clay rocks and
some others of a similar type of plasticity. This most favora-
ble state should not be expected uniformly in the rocks from
Yonkers southward.

(b) The rock may remain open and a permanent 'and
strong line of underground drainage be established. This is
characteristic of brittle rocks, chiefly of coarse texture. It
would probably not be found in the rocks "under discussion.

(c) A state between these extremes may be found in which
the fractures persist and decay may even affect their walls;
but, on account of the physical nature of the rock or its min-
erals, waterflow along the disturbed zone is much impeded.
It is believed that this is the condition obtaining at considerable
depth in the more disturbed regions along the line of the
pressure tunnel, notably at the northwest corner of Central
park and in the lower east side district. Tunnelling should be
entirely practicable through narrow belts of such rock, but with
increased cost and slower progress.

79

(4) Rock weathering, which here takes the form chiefly
of decay, with disintegration as a subordinate consequence.
The zones of deep decay may be connected directly with frac-
tures or faults, or may characterize a kind of rock or a par-
ticular situation. Of these we have several, confined, however,
to two of the formations of the region — the Manhattan schist
and the Inwood limestone.

What has been said immediately above applies here, as
the state of the minerals is due to " weathering " in large part.
The rocks, except the purer phases of the Inwood limestone,
contain varying and sometimes large amounts of one or other
variety of mica. The flaky character of this mineral diminishes
the number of instances in which rock wounds heal completely,
as in clay rocks, but the micas cause great obstruction to water
passage.

Weathering consists in part in the formation of clay as a
constituent of the rock, the loosening of the micas, with con-
sequent weathering of the binder in the rock and frequently
considerable disintegration. When carried far in broad belts,
this would render the rock unfit for excavation at the depths
contemplated here. But in the only two portions of the field
where it is known at tunnel grade, it is believed that a deeper
tunnel will entirely avoid the evil.

With respect to the injurious features discussed under the
various headings above, the order of the rock; with the best
rock first, is Yonkers gneiss, Fordham gneiss (these two about
equal in quality) , Manhattan schist, Inwood limestone. •

(5) Soft spots or pockets. It is undeniable that in the
Manhattan schist there are rare seams of soft material, chiefly
micaceous. One such lens was encountered at the site of St.
John's Cathedral; two were met in the subway at Park ave-
nue, between 38th and 39th streets. All the cases of which
we can obtain authentic record were comparatively shallow.

A number of such pockets are alleged to have been encoun-
tered entirely on the testimony of borings. Stories are told
of the sudden dropping of drills many feet after passing hard
rock. But it must be remembered that several causes may
contribute to this apparent effect. In the first place, it has often
happened that drills, after working laboriously and slowly in
hard quartz and feldspar rocks for some time, may suddenly

80

encounter a band of soft but sound fock, highly micaceous in
character, into which the bit, previously working under all the
power possible from the particular machine, forces its way
with great readiness. So sudden is the change that the drill
appears to jump or fall. And if the soft band lies parallel to
the axis of the drill, or vertical in most of the work done in
New York, the bit may go for a long distance in such soft
rock and apparently develop a great mass of it, while in
reality there is but a narrow and harmless band.

A second cause is intentional or unintentional error in
recording progress. In not a few instances, where proper
care has not been taken in making records, it is found that
several feet of progress are quite unaccounted for. The figures
for the day must show the point attained at the end of work,
so somewhere there must come a discrepancy, which can be
best labelled as soft ground, or more likely a " cave."

Nevertheless, such soft spots may occur in rocks such as
the schists and gneisses of New York. There is no way to
prophesy their presence, short of sinking holes to grade, at
intervals of every few feet — a manifest impracticability. It
is only necessary to rest upon the undeniable fact that, in all
the excavating work in this city, so few have ever been dis-
covered and none have been met that proved unsurmountable
barriers to completion of the work. In other words, the prob-
ability of encountering such pocket is so small as to be negligi-
ble. Should one be met, it can certainly be either penetrated
or passed without taxing the engineering skill of to-day.

Location of Pressure Tunnels

It may be said that pressure tunnels can be constructed and
maintained in almost any rock that has a fair degree of hard-
ness, freshness, impermeability, freedom from faults and frac-
tures.

Whereas, in New York City a number of rock formations
are present, each different in some respects from the others,
the following choice is worth making :

(1) Hard formations should be chosen rather than soft.
The latter are subject both to deeper erosion and to deeper
decay.

81

(2) Ridges should be followed rather than valleys. They
are more likely to have a shallow zone of weathering, because
the rock is so hard and resistant that it has thus been able to
withstand the action of the elements.

(3) Dense formations should be chosen rather than permea-
ble ones. It is but reasonable a rock which permits least water
to pass through it is best adapted to excavation.

(4) As few contacts as possible should be crossed. While
in individual cases contacts may be as favorable as the adja-
cent or any other rock, contacts are weak and permeable in
so many instances that they are naturally regarded with
suspicion.

(5) Contact zones should be avoided. They are often weak
and subject both to mechanical shattering and to chemical
decay, the whole end of which is to admit water.

(6) A sufficient rock cover should be provided in pressure
tunnels. For the hydraulic conditions found in the plan under
consideration, it is believed that at least 100 and preferably
ISO feet of sound rock should overlay the tunnel.

Exploration of Rock

In our opinion the exploratory work has been unusually
thorough. We know of no other large city area of difficult
lithology and structure* the rocks of which have been studied
with so great care or in such detail.

Stratified rocks may usually be. assumed to change little
along the strike for considerable distances. In this instance
there is everywhere a gentle pitch southward, thus bringing
new strata to the surface in this direction as well as east and
west. And for this reason the sections brought up in suc-
cessive drill holes along the general strike of the rocks vary
somewhat. But the rocks are so persistent and similar in char-
acter for long distances north and south that unless for special
reasons holes at shaft sites (4,000 feet apart) are often suf-
ficient.

In exploring across the structure a different condition ob-
tains. Here diverse layers are met in quick succession, and
the holes may require to be close enough together to pene-
trate most or all of these layers.

82

Opinion

Our answer to the question " Is the proposed Manhattan
tunnel practicable from a geological standpoint?" is that it is
practicable, that it is superior to others originally contemplated
through the same Boroughs, and that its location, both geo-
graphically and in depth, has followed quite adequate explora-
tion, except in the few places indicated above.

Ill

Answer to the question, " Which, in your opinion, is the
better route for a pressure tunnel, if constructed (a) from
Hill View reservoir, through Queens to Brooklyn, or (b) from
Hill View reservoir through Manhattan island to Brooklyn ? "

We would unhesitatingly answer the latter, speaking from
a geological standpoint. Our judgment from the engineering
viewpoint is given in our report.

It is perhaps unfortunate that no drill holes have been
sunk to test this route systematically ; but it could hardly alter
final judgment in the matter. The engineering evidence is so
overwhelmingly in favor of carrying a pressure tunnel, if one
be constructed, through Bronx and Manhattan, that only
marked unsuitability of the rocks there, coupled with the
presence of unusually favorable rock and structures along the
line proposed through Queens to Brooklyn, could reverse the
decision that the present route is the better of the two.

But the rock conditions, instead of being better along the
pipe-line first proposed to Queens, are comparatively unfavor-
able. * This much we know from surface field evidence, without
waiting for borings : ( 1 ) The topography is less advantageous,
indicating no lines of especially firm rock to be followed. (2)
The presence of two deep valleys to be crossed adds no advan-
tage to this route. (3) In the field the rocks are seen to be in
a condition by no means so firm and fresh as those of western
Bronx and Manhattan, which probably accounts in large meas-
ure for the low relief of the surface. (4) A far higher ratio
of cross-cutting to drifting on the strike of the rock would be
necessary, with its attendant uncertainties. (5) The cross-
ing to Queens, wherever it might be, would be in unfavorable
ground. A downfolded belt of Manhattan schist extends

83

southward from Morrisania, narrowing and steepening as it
proceeds, and the tunnel would be obliged to pass for a con-
siderable distance along or obliquely across this syncline.
Again, a folded projection of Fordham gneiss encircled by
Inwood limestone, lies on the east of this fold, and the tunnel
must cross this area obliquely, including a submarine traverse
several times as long as the proposed route under the lower
part of East river. This is at the beginning of the disturbed
zone that is met in the "lower east side section " ; but at the
north, it is nearly two miles across in the direction to be fol-
lowed by the tunnel. (6) While the rock in the extreme west-
ern part of Long Island City is Fordham gneiss, it is not on
the whole of quite so good quality as in The Bronx, being cut by
many granite dikes. (7) The configuration of the rock floor
made by the surface of the gneiss in Queens. Unconsolidated
sands and clays of comparatively recent age cover the larger
part of the gneiss, and the hard rock floor pitches rather rap-
idly down southeastward.

With a large number of doubtful or unfavorable points
certain to be raised against the route as seen from even sur-
face rock conditions, with an entire lack of detailed informa-
tion of the character of the rock, such as drill-holes would
furnish, it is our opinion that the idea of a pressure tunnel
from Hill View to Queens and Brooklyn, crossing under the
East river at its northern end, should not be given serious con-
sideration at this time.

84

APPENDIX B

RESULTS OF ROCK BORINGS ALONG LINE OF

PROPOSED TUNNEL

In the course of exploration for tunnel location diamond
drill holes have been put down at all points where they were
either essential or valuable for discovering the structure and
condition of the rocks at and near the line of the tunnel. Some
of these were comparatively shallow. In places where out-
crops or other sources of information show sound rock at or
close to the present surface of the ground it is obviously un-
necessary to sink deep holes every few feet.

In two classes of situations, however, holes are required
either to the proposed grade of the tunnel, or to such depth
as proved conclusively the kind and condition of the rock.
In a few sections these features were so little known at the
beginning of the field work conducted by the Board of Water
Supply, and the rock conditions were deemed so important in
solving the problem of location, that unusually numerous bor-
ings were made, some shallow, some deep. Such districts were
(1) the Harlem River crossing (in spite of information fur-
nished by earlier tunnel construction) ; (2) from 126th street
to 106th street, embracing Morningside park and the Man-
hattanville valley; (3) the "lower east side section," from
Bowery and Delancey street to Clinton and Cherry streets;
(4) East River crossing.

Of these (1) the Harlem River crossing proved to have
so firm and fresh rock in the river bed that it was unneces-
sary to sink more than two holes to tunnel grade, in or close
to the river. (2) The topography at the north end of Morning-
side park, and the topography and rock distribution at the
south end and adjacent to the northwest corner of Central
park, gave reasonable possibility of finding deep rock decay
and cross faulting with crushing of the wall rock. Hence in
both portions of that district several deep holes were sunk,
with the result of finding sound rock at the place and depth
proposed at the north end, and of indicating at the south
end that the required conditions will be met by depressing
the tunnel grade slightly. (3) The third district is still under
investigation, and the conclusions reached by us from all the

85

evidence at present available are stated in detail elsewhere
(Appendix C). It can be said here that it is the only sec-
tion besides the above mentioned in which the tentative plans
drawn up by the Board of Water Supply may require to be
amended by reason of rock conditions. (4) The crossing of
East river at the point proposed will not be accompanied by
any of the uncertainties that exist in regard to the rocks be-
neath all portions of the river north of 17th street. For here
the river is in Fordham gneiss, a rock of pfoved worth as
ground for any excavation; while to the north faulted and
shattered and decayed rocks occupy the river everywhere. The
drill holes started in and adjacent to the river from the foot
of Clinton street to Brooklyn discovered rock so sound and
firm that deep drilling would have been superfluous.

Turning now to the details recorded in the form of drill
cores, the following statement summarizes a complete study
of all such throughout the line and a tabulation of the results.

From the downtake shaft at Hill View to Manhattanville
the rock met at tunnel grade is sound, and the hight of good
rock over the tunnel is adequate. This is equally true of all
of the four geological formations traversed. At 125th street,
where a deep cross-valley intersects the line of the tunnel,
decay has proceeded to within 93 feet of the roof of the tun-
nel ; but the latter itself would be excavated in sound schist.

The holes on 106th street show a zone of shattering and
some decay, consequent upon the proximity of an anticline of
limestone to the north, pitching southward underneath the
schists cut along 106th street. Hole 60 shows rock that is
alternately decayed and hard, but it would not be impossible
to drive the tunnel through it.

From 106th street and Central park, sound rock and ample
cover are found until the " lower east side section " is reached.
The East River crossing and the course in Brooklyn are in
good rock.

86

APPENDIX C

DISCUSSION OF THE GEOLOGY OF THE " LOWER

EAST SIDE DISTRICT," WITH REFERENCE

TO DEEP TUNNELLING

General Statement

From Hunt's point and eastern Mott Haven, southward
across Randalls and Wards islands and along the submerged
valley of East river, is a folded zone in which are involved the
Fordham gneiss, Inwood limestone and Manhattan schist. The
zone is broad in the north and folding less severe. Gradually
the folds pinch closer as one proceeds southward, until where
cut by the line of the proposed pressure tunnel the rocks are
not only close folded, but crushed and faulted by breaks that
strike nearly or quite parallel to the strata. With increased
intensity of disturbance comes a decrease in the breadth of the
poor ground, but an increase in the depth of the zone of decay.
The breadth of ground regarded as in any way objectionable
at the depth proposed is 4,000 feet between the extreme points,
which distance includes much good rock, but in considering
the zone across which there may be required a depression of
the tunnel grade, it is necessary to include this in full.

The district is still under exploration. Its geology has
been reported upon from time to time to the Board of Water
Supply by its geologist. It is the aim of this appendix merely
to discuss such features as have most immediate relation to
the problem of cross-tunnelling through this section of the
City. As will be seen below, they are the data that give ground
for the opinion expressed at the end of this appendix.

The disturbed zone leaves East river along the water-front
from the foot of 33rd street to that of 17th street (approxi-
mately), running thence southward and leaving the island
along the water-front from Rutger's slip to approximately
the foot of Wall street. East of this, Fordham gneiss extends
across from Brooklyn, furnishing secure rock for excavation
purposes.

While the structure is important, it is even more necessary
in this connection to determine certain other features, in part
connected with the structure. These are especially (1) the

87

total length of poor ground, (2) depth of decayed, shattered
or otherwise permeable rock, location and dimensions of such
rock as bids fair to create trouble in constructing or maintain-
ing the tunnel.

In brief, the questions raised may be answered in part by
saying (1) that for a short stretch the rock floor has been
eroded to considerable depths, the overburden being uncom-
pacted and pervious material, (2) that there are three lines,
along which fracturing and probably faulting have occurred,
nearly parallel with the strike of the formations, shattering
the adjacent rock; (3) that as a result of this faulting and
crushing, decay has proceeded locally to a great depth below
bedrock surface.

It is found that the zones of crushing and decay are in
the form of narrow wedges, thinning downward, ultimately
to disappear. It is further established, by gross and micro-
scopic examination of cores and rock samples, (a) that decay
is subordinate to mechanical crushing; (b) that the individual
zones of disturbances are narrow at tunnel grade, but are still
to be detected in two cases ; (c) that the condition of the rock,
especially as seen under the microscope, indicates with cer-
tainty that within a slightly increased depth the rock will be
found entirely sound.

Details of Holes

All the shallow holes of Delancey street show much decayed
rock ; but none, extend far below 200 feet, and the proposed
tunnel grade is 600 feet. This constitutes the western zone
of disturbance. Three holes on Delancey street penetrating
Fordham gneiss show sound rock below 150 feet.

The tunnel is planned to turn from Delancey street along
Allen, so as to keep for as long a distance as possible in Ford-
ham gneiss and still to reach the river by the shortest prac-
ticable route under the streets.

The second strip of bad ground is along Hester street,
from Allen to Suffolk. But the thickness of sound rock above
tunnel grade is ample except in Hole 202, on Hester street,
west of Suffolk. The bottom of this, approximately at grade,
is in fairly sound gneiss, which becomes broken upward and
at 100 feet above the tunnel is badly weathered.

88

This hole is situated in the middle zone of crushing and
decay. The rock is sound enough for tunnelling at the depth
proposed for the tunnel, but gives little firm rock above it
across one short stretch.

The third or eastern zone of disturbance is the most pro-
nounced at tunnel grade. In Hole 207, on Henry street, be-
tween Montgomery and Clinton streets, the rock is badly
weathered to 100 feet above grade. Thence downward it is
broken considerably, but microscopic examination shows the
minerals composing the rock to be fairly fresh. In Hole 211,
on Clinton street, between Madison and Monroe streets, the
bottom is in firm and tight Fordham gneiss, and for over 100
feet upward the rock is undecayed, but is broken considerably.

Microscopic Examination of Rock Cores

The solid core recovery from certain of the holes, in which
decay seems to have gone on deepest, is not large in amount,
and gives excuse for supposition that the rock may be widely
decayed to great depths, especially along the shear zone met
in Holes 207 and 211. But microscopic study of portions of
the recovered core shows clearly that the chief action upon the
rock has been a mechanical fracturing, decay being largely
consequent upon it and both characterizing a narrow strip of
ground and probably closely limited by it.

In Hole 207, from 532 feet to the bottom, the recovery was
in short bits. In the slide the hornbend gneiss, which begins
at 532 feet, is seen to be fractured, but not badly in detail.
Its minerals are rather generally decayed and hydrated, espe-
cially at the margins of the pieces, but, while the rock would
not furnish good working ground, it is by no means so bad as
much rock that is met in deep excavations, as in mining.

In Hole 211, the rock, from 571 to 580 feet, examined
microscopically, is found to be quite fresh and tight, slight
decay of the edges of the feldspar pieces being the only evi-
dence of change. Unless cut by pronounced rifts it should
behave excellently in tunnelling.

Summary of Interpretation

For approximately 4,000 feet along the line as now laid
down the tunnel must traverse a zone within the boundaries

89

of which, while there are sound bands, the rock is more or
less sheared and crushed in three places. In two of these the
disturbance is noticeable to at least the proposed tunnel grade.

The evidence shows plainly that these disturbed zones are
narrow and sharply defined, but that they are separated by
much sound rock. The opinion is further justified by field
evidence that the zones are narrowing downward and should
disappear shortly below.

Such information as can be had does not favor shifting
the line of crossing of this zone to points north or south, in
the hope of easement of the engineering difficulties. The
ground for miles up East river is of the same general char-
acter, and the distance to be crossed in any traverse made to
the north is greater.

It remains, therefore, to make a tentative decision (1)
whether the tunnel is practicable along the course and at the
depth proposed; (2) if not, whether altering the grade of the
tunnel in this section would render the route practicable; (3)
whether, if the present plan be feasible, changing the grade of
the tunnel in this section would be advantageous from the
standpoints of time of completion, cost, safety of construction
and permanence.

Opinion

With regard to (1) it is our opinion that the tunnel can
be constructed along the course and at the depth proposed.
This also disposes of point (2).

The last question brought up is easy to answer. It is un-
deniable that at the proposed tunnel grade there will not be
at all points the 100 or 150 feet of sound rock overhead that
is desired. The poor ground could, in our opinion, be tra-
versed safely, even if special reinforcement were necessary.
But the increased cost and the uncertainty of permanence must
be weighed against such increase in cost and in time of com-
pletion as will result from a depression of the tunnel grade.

90

APPENDIX D

PRESSURE TUNNEL PLAN TO DELIVER 500 MIL-
LION GALLONS DAILY FROM HILL VIEW RES-
ERVOIR, AS RECOMMENDED IN REPORT OF
BOARD OF WATER SUPPLY TO THE
BOARD OF ESTIMATE AND APPOR-
TIONMENT, DATED NOVEMBER

15, 1909

Historical

In the report of the Board of Water Supply dated October
9, 1905, to the Board of Estimate and Apportionment, a sum-
mary is given of the proposed system to obtain a supply of
water from the Catskills of 500 M. G. D. In this report pro-
visions were made for supplying Brooklyn with 100 M. G. D.
and Richmond with 20 M. G. D. The distribution of the
remaining 380 M. G. D. was left for future consideration.

The plan proposed a steel pipe-line from the Hill View
reservoir to the East river, a 10-foot tunnel under the East
river at Port Morris to Long Island, and a steel pipe-line con-
necting the tunnel to Forest park, in Brooklyn.

A cast-iron pipe-line was to extend also from the tunnel
to the Narrows, passing under them to Richmond. The cost
of this work was estimated at $10,224,000.

A reservoir was proposed at Forest park, Brooklyn, but
no provision was made for it in the estimate. No provision
was made for a reservoir in Richmond, made necessary for
this plan, nor were pipe-lines provided for a distribution of
the 100 M. G. D. from Forest park to Brooklyn.

To provide for these reservoirs and distributing pipe-lines
would cost approximately $5,000,000, which, added to the
original estimate of $10,224,000, makes $15,000,000, the cost
of delivering 120 M. G. D., or about one-quarter of the Catskill
supply.

The location of this system is indicated in brown on Sheet
4, Accession 6663. The time of completion would be about
five years, owing to the length of the Port Morris tunnel cross-
ing under the East river and the preliminary investigation
necessary before the letting of contracts.

To complete this preliminary work, and in place of it
to provide in a studied and best manner for the permanent

91

distribution needs of the City, the Board of Water Supply, by
its letter of November 15, 1909, proposed the work which is
the subject of the estimates herewith presented. This letter
is based on the report of the Chief Engineer of the Board of
Water Supply of November 1, 1909.

Under date of December 8, 1909, the majority of a com-
mittee consisting of the Chief Engineer of the Department of
Finance, the Chief Engineer of the Board of Estimate and
Apportionment, the Chief Engineer of the Board of Water
Supply and Assemblyman Lindon Bates, Jr., reported to the
Board of Estimate and Apportionment ; while the report of the
minority, consisting of Assemblyman Lindon Bates, Jr., was
presented December 10, 1909.

Under date of February 2, 1910, the Chief Engineer of
the Department of Water Supply, Gas and Electricity reported
on this same project to the Honorable Commissioner of the
Department of Water Supply, Gas and Electricity.

As stated in the beginning of the main report, of which this
is Appendix D, the present Commission of two engineers
and a geologist was appointed by letters from a Committee of
the Board of Estimate and Apportionment, appointed March
4, 1910.

Estimate

The plan here considered for the delivery of water to all
the Boroughs calls for a pressure tunnel, situated at least 150
feet below the surface of the "rock floor." Starting from
Hill View reservoir, to pass under the Harlem river, near
High Bridge, thence extending under the west side of Man-
hattan to Central park, thence under Central park and the
centre of Manhattan to Delancey street, crossing under the
East river to Brooklyn, and terminating near Flatbush and
Lafayette avenues.

From this point a 66-inch steel pipe extends to Fifth and
Prospect avenues, whence a 48-inch cast-iron pipe is employed
to 79th street and the Narrows.

A 36-inch flexible joint pipe is used under the Narrows
to Richmond, where a 36-inch cast-iron pipe delivers to a
reservoir at Silver lake, at an elevation of 225 feet.

The line to Queens consists of a 66-inch steel pipe from the
end of the tunnel to Willoughby and Carlton avenues, then

92

reducing to a 48-inch cast-iron pipe, extending to Thompson
and Fisk avenues.

The size and length of tunnel and pipe-line under this sys-
tem are as follows:

PRESSURE TUNNEL

Limits of Section

Size of
Tunnel

» «

Feet Inches

Length
in Miles

Hill View reservoir to City line 16

City line to 135th street 15

135th street to 40th street 14

40th street to 24th street 13

24th street to Delancey and Allen streets 12

Allen and Delancey streets to Platbush avenue and

Lafayette avenue, Brooklyn 11

.40
7.31
4.94

.40
1.36

3.24

PIPE-LINES

Limits of Section

Size of
Pipes

Length
in Miles

queens line

Tunnel terminal to Carlton and Willoughby avenues. . 66-inch steel .69

Willoughby to Fisk and Thompson avenues 48-inch cast iron 7.99

RICHMOND LINE

Tunnel terminal to Fifth and Prospect avenues 66-inch steel 1.72

Prospect avenue to Narrows 48-inch cast iron 3 . 51

Crossing the Narrows 36-inch submerged 1 .88

Narrows to Silver Lake reservoir 36-inch cast iron 1 . 70

The construction shafts are located approximately 4,000 feet
apart and will be used as uptakes from which, in an emergency,
the entire supply for any Borough can be supplied.

The large-sized tunnel goes to the 135th street uptake shaft,
so that the present Croton tunnel can be put out of service for
cleaning or repairs if desired, and the supply furnished through
the new tunnel.

Three hundred million gallons daily can be delivered to
Brooklyn with a frictional loss of 3 feet per mile, and the
tunnel is of sufficient size to deliver the full 500,000,000 gal-
lons daily with an additional loss of about 15 per cent.

The following pressure will be available in the different
boroughs :

Boroughs

250 Million
Gallons Daily

500 Million
Gallons Daily

The Bronx

Upper Manhattan.
Lower Manhattan.

Brooklyn

Queens

Richmond

Feet

Feet

290

285

283

275

280

270

280

265

265

245

260

225

93

At each uptake automatic pressure controlling-valves will
.regulate the pressure delivery as deemed advisable, and no
changes in the distributing systems will be made necessary.

The estimated time of completion is four and one-quarter
years for this plan, at a cost of $26,000,000.

A detailed estimate of cost is as follows:

Cost Estimate of City Aqueduct Pressure Tunnels to
Deliver 500,000,000 Gallons Daily

cost per linear foot of tunnel

Diameter Length

Feet

Tunnel Shaft

Total

Total Cost

16 feet 7 inches 2,112

15 feet 38,597

$187.47 $34.40
162.37 34.40
150.27 34.40
139.97 34.40
122.77 34.40
113.37 34.40

$221.87
196.77
184.67
174.37
157.17
147.77

$467,589.00
7,594,732.00
4,816,747.00

14 feet 26,083

13 feet 2,112

368,269.00

12 feet 7,181

1,128,638.00

11 feet 17,107

2,527,901.00

Total

$16,904,876.00

Easements, right-of-way, etc. . . .
7 shaft sites at $100.000

150,000.00
700,000.00

2 drainage shafts

250,000.00

Twenty per cent, for engineering

and contingencies

$18,003,876.00

3,600,000.00

Cost of pressure tunnels

$21,605,000.00

PIPE-LINES IN EXTENSION OF PRESSURE TUNNELS

Size

Length
in Miles

Cost
Per Mile

Total

66-inch steel

2.4

$173,000.00
143,000.00
110,000.00
275,000.00

$415,000.00

48-inch cast iron

36-inch cast iron

36-inch submerged

11.6

1.7

2.0

1,659,000.00
187,000.00
550,000.00

Twenty per cent, for engineering

and contingencies

$2,811,000.00

562,000.00

$3,373,000.00

DISTRIBUTION RESERVOIR IN THE BOROUGH OF

RICHMOND

Reservoir in Richmond, 400,000,000 gallons daily capacity $750,000.00

Land 300,000.00

$1,060,000.00

Twenty per cent, for engineering and contingencies 210,000.00

$1,260,000.00

Grand total $26,238,000.00

Say $26,000,000.

94

APPENDIX E

PIPE-LINE TO DELIVER 500,000,000 GALLONS DAILY"
—AN ALTERNATE PLAN PROPOSED BY THE
BOARD OF WATER SUPPLY IN THEIR
REPORT OF NOVEMBER 15, 1909

•

This plan substitutes pipes to deliver 500,000,000 gallons
daily in place of tunnels as in other plan, delivery to be made
at the same pressure.

The largest pipe that can be used, owing to the difficulties
of placing among existing subsurface structures, is a 66-inch.

A 10-foot tunnel crosses under the Harlem river to deliver
the Manhattan supply and under the East river to supply from
The Bronx to Queens and Brooklyn. An 8-foot tunnel ex-
tends under the East river to cross-connect lower Manhattan
with Brooklyn.

Sixteen 66-inch pipes lead from Hill View reservoir ; seven
extend to Manhattan, and seven to Long Island, leaving two
for The Bronx supply.

The life of steel pipes is estimated at thirty-five years,
after which time they would have to be renewed. The interfer-
ence with business in laying these large pipes would be con-
siderable and the interference with subsurface structures pres-
ent and to come, especially subways, would be great.

It is estimated that this system can be completed in from
four to five years, the controlling factor being the long tunnel
under the East river, near Port Morris. No diamond drill
borings have been made to date on the line of this tunnel.

The detailed cost estimate of this system is given below.
The total is approximately $47,000,000, or almost double that
of the pressure tunnel, giving an equal hydraulic service. Even
with making due allowance for possible deferment of installa-
tion of pipe-lines, since all of them would not be required
immediately, the " present worth " of the pipe-line system is
greater by $10,000,000 than the pressure tunnel.

95

ESTIMATED COST OF PIPE-LINE TO DELIVER
500,000,000 GALLONS DAILY

Size of Pipe

Length
Miles

Cost
Per Mile

Total Cost

Pipe Lines

Steel pipe, 66-inch, Manhattan. 44.5

Steel pipe, 66-inch 166.0

Steel pipe, 66-inch, submerged.. 0.3

Cast-iron pipe, 48-inch 3.8

Cast-iron pipe, 36-inch 1.7

Pipe, 36-inch, submerged 2.0

Fifteen per cent, for engineering

and contingencies

$209,000.00
173,000.00
350,000.00
143,000.00
100,000.00
250,000.00

$9,300,000.00
28,718,000.00
105,000.00
543,000.00
170,000.00
500,000.00

$39,336,000.00

5,900,000.00

$45,236,000.00

Size of Tunnel

Length
Miles

Cost
Per Mile

Total Cost

Pressure Tunnel

10-foot tunnel

8-f oot tunnel

Easements and right-of-way.

Twenty per cent, for engineering
and contingencies

0.8 $1,000,000.00
0.5 900,000.00

$800,000.00

450,000.00

50,000.00

$1,300,000.00

260,000.00

1,660,000.00

Grand total $46,796,000.00

96

APPENDIX F

DETAILED COSTS OF (1) PRESSURE TCXXELS,

8 EEET TO 16 FEET 7 INCHES DIAMETER,

(2) PIPE, 66-IXCH STEEL AND 48-

IXCH CAST-IRON, (3) SHAFTS

ESTIMATED TUNNEL PRICES PER LINEAR FOOT FOR CITY PRESSURE TUNNELS

Diameter

Y«~ft~ 7 in7 15 ft. lTftT T3~fT ^T2 ft. 11 ft. 10 ft. 9 ft] S~ft?
^

Excavation $117.00 $96.30 $86.40 $78.30 $66.60 $59.40 $49.00 $39.93 $31.90

Trimming 2.16 2.16 2.16 2.16 2.16 2.16 2.16 2.16 2.16

Concrete 48.40 44.00 41.80 39.60 34.10 31.90 28.53 26.60 23.63

Grouting 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.75

Temporary timber. 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00

Steel lining .36 .36 .36 .36 .36 .36 .36 .36 .36

Dry packing .80 .80 .80 .80 .80 .80 .80 .80 .80

Pumping 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00

Testing 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00

Total cost, tunnel.. $187.47 $162.87 $160.27 $189.97 $188.77 $118.87 $89.80 $88.80 $77.60

Total cost, shaft. . . 84 40 84.40 84.40 84.40 84.40 84.40 34.40 34.40 34.40

Total cost $331.87 $106.77 $184.67 $174.37 $167.17 $147.77 $134.00 $138.00 $113.00

ESTIMATED COST OF SHAFT SINKING FOR CITY AQUEDUCT TUNNELS

Labor, per shift $100.00

Plant, power ana overhead charges 40.00

Total cost per shift $140.00

Working two shifts only and with progress of 35 feet per month

(per foot of shaft) $210.00

Powder 8.00

Timbering 15.00

Disposal 12.00

$246.00

Contractor's profit, contingencies, etc 55.00

$300.00

Concrete plug, 175 feet long (per foot of shaft) $40.70

Concrete lining 16.30

Chamber 5.20

Valves and regulators 7.50

Uptake pipe, mortar lined 7.30

Bronze cut-off valve 58.00

136.00

Total costs of shafts per linear foot $435.00

Average depth of 23 shafts, 320 feet.

Length of tunnel, 93,112 feet.

Cost of shafts per linear foot of tunnel, $34.40.

97

DETAILED ESTIMATE OF COST OP 66-INCH STEEL
AND 48-INCH CAST-IRON PIPE

Cost Per
Linear Foot

66-inch

48-inch

Steel

Cast-iron

$17.00

$14.00

1.00

.55

1.55

1.05

2.52

2.50

2.25

1.00

.75

1.50

.85

.47

.50

.30

3.00

2.20

Pipe delivered

Special structures

Excavation, earth

Sheeting and bracing

Substructures

Laying

Disposal

Back-fill

Pavement replacing

Total

Fifteen per cent, engineering and contingencies.

Total cost per linear foot

$29.42

3.41

$32.83

$23.57

3.54

$27.11

The above are average prices for The Bronx, Brooklyn
and Oueens.

For Manhattan the average excavation would be about one-
half rock and prices would be:

66-INCH

Steel

48-inch
Cast-iron

Average as above $32.83

Add for one-half rock, etc 6.77

Total .cost per linear foot $39.60

$27.11
3.49

$30.60

98

APPENDIX G

PROGRESS IN TUNNELS AND SHAFTS IN PRE-
VIOUS SIMILAR WORK— PROGRESS ASSUMED
FOR THIS REPORT— TIME OF COMPLE-
TION OF PRESSURE TUNNELS

Shaft Progress

Average monthly progress from start to finish:
Wallkill, 6 shafts, 67.5 feet per month.
Moodna, 3 shafts, 66.6 feet per month.
Rondout, 8 shafts, 63 feet per month.

New York Subway — Notes by Mr. Deyo

104th street, 52 feet deep; average progress, 26 feet per
month.

167th street, 91 feet deep; average progress, 23 feet per
month.

181st street, 110 feet deep; average progress, 22 feet per
month.

181st street, 158 feet deep; average progress, 45 feet per
month.

Tunnel Progress

Rondout pressure tunnel, average progress, 207 feet per
month.

Wallkill pressure tunnel, average progress, 230 feet per
month.

Pennsylvania crosstown tunnels, average progress, 180 feet
per month.

Sewer tunnel, Yonkers, average progress, 200 feet per
month.

Assumptions for This Report

Sinking shaft, 35 feet per month.
Driving tunnel, 150 feet per month.
Concreting tunnel, 300 feet per month.

Progress

Work within the City limits cannot be prosecuted as advan-
tageously as in open country. The City ordinances prohibit
blasting between sunset and sunrise. This interferes mate-

99

rially with progress. In shaft sinking it means one idle shift
per day. In residential districts it is doubtful if drilling in
shafts can be done after 11 p. m.

Time for Completion of Controlling Sections of Tunnels

for City Aqueducts

critical shafts

No. 7, 380 feet deep, Sedgwick avenue; No. 8, 355 feet
deep, Speedway; No. 9, 430 feet deep, Colonial park, residen-
tial; No. 10, 400 feet deep, St. Nicholas park, residential;
No. 11, 400 feet deep, Morningside park, residential; No. 20,
650 feet deep, Allen and Delancey streets, residential; No. 21,
650 feet deep, East river.

shaft no. 7

Preparation of contract, 6 months; time of awarding con-
tract, 2 months ; assembling plant, 2 months ; sinking shaft 380
feet, 11 months; driving 2,600 feet of tunnel, 17.4 months;
concreting 2,600 feet of tunnel, 8.6 months ; refilling and grout-
ing shaft, 2 months. Total, 49 months, or A%. years.

shaft no. 9

Preparation of contract, 6 months; awarding contract, 2
months; assembling plant, 2 months; sinking shaft 430 feet,
12.3 months; driving 2,000 feet of tunnel, 13.3 months; con-
creting 2,000 feet of tunnel, 6.7 months ; refilling and grouting
shaft, 2 months. Total, 44.3 months, or 4 years.

shaft no. 20

Preparing contract, 6 months; awarding contract, 2
months; assembling plant, 2 months; sinking shaft 650 feet,
18.7 months; driving 2,000 feet of tunnel, 13.3 months; con-
creting 2,000 feet of tunnel, 6.7 months ; refilling and grouting
shaft, 2 months. Total, 50.7 months, or A%. years.

100

APPENDIX H

COMPARATIVE COST OF PRESSURE TUNNELS TO
DELIVER 500,000,000 GALLONS DAILY AND
250,000,000 GALLONS DAILY FROM THE
HILL VIEW RESERVOIR THROUGH
THE BRONX AND MANHAT-
TAN TO BROOKLYN

PRESSURE TUNNEL OF 500,000.000 GALLONS DAILY CAPACITY

Size op Tunnel L =™™ Per C ^I le Total Cost

16 feet 7 inches.

15 feet

14 feet

13 feet

12 feet

11 feet

0.40

$1,171,000.00

$468,000.00

7.31

1.039,000.00

7,595,000.00

4.94

975,000.00

4,816,000.00

0.40

921,000.00

368,000.00

1.36

830,000.00

1,129,000.00

3.24

780,000.00

2,527,000.00

$16,903,000.00

Easements and right-of-way 150,000.00

Seven shaft sites at $100,000 700,000.00

Two drainage shafts 250,000.00

$18,003,000.00

Twenty per cent, for engineering and contingencies 3,601,000.00

Total $21,604,000.00

PRESSURE TUNNEL OF 250,000,000 GALLONS DAILY CAPACITY

Size of Tunnel ^™ p^gg.. Total Cost

1 1 feet

7.72

$780,000.00
710,000.00
650,000.00
600,000.00

$6,022,000.00

10 feet

4.94

3,507,000.00

9 feet

1.76

1,144,000.00

8 feet

3.23

1,938,000.00

$13,611,000.00

150,000.00

Two drainage shafts

250,000.00

Seven shaft sites at $100,000

700,000.00

$13,711,000.00

Twenty per cent, for engineering and contingencies 2,742.000.00

Total $16,453,000.00

— equals 76 per cent, of cost of 500,000,000 gallons daily
tunnel.

The line followed by these two tunnels is the same as shown
on Sheet 4, Accession 6663.

101

APPENDIX I

PIPE-LINE SYSTEM TO DELIVER 250,000,000 GAL-
LONS DAILY, OR THE FIRST INSTALL-
MENT OF THE CATSKILL WATER

SUPPLY

This system provides for eight 66-inch steel pipes extend-
ing from Hill View reservoir into The Bronx. Three lines of
pipe are carried into Manhattan, using submerged pipe-lines
under the Harlem river, and three extending to Queens by
means of an 8-foot tunnel under the East river, near Port
Morris. (See Sheet 4, Accession 6663.)

Pipe-lines are provided in Manhattan so as to distribute
to the high and low pressure service.

In Queens and Brooklyn, pipe-lines are extended to points
where the supply is needed, and a line is also carried through
Brooklyn and under the Narrows to Richmond.

The same loss of head would take place as in the tunnel
system.

No tunnel is provided to cross-connect the Brooklyn and
Manhattan supplies.

The time of completion of this system would be about five
years owing to the long tunnel under the East river at Port
Morris and to the fact that the preliminary investigations of
this tunnel site would have to be made. The estimated cost
is shown below and indicates that the expense of this system
is within $1,600,000 of the pressure tunnel of twice the capac-
ity.

Estimated Cost of Pipe-Line System to Deliver 250,000,000
Gallons Daily to The Bronx, Queens, Brooklyn

and Richmond
maximum size of pipe, 66 inches

Sl2E OF P ' PE L M?le T s H PerMile Tqtal Cost

66-inch steel 82.0 1*209 000 00 } S14.810.000.00

48-inch cast iron 20.0 { }e! qoo 00 j 3,000,000.00

36-inch cast iron 4.0 lOO.OOoW 400,000.00

66-inch, submerged 0.5 350.000.00 175,000.00

36-inch, submerged 2.0 250,000.00 500,000.00

$18,885,000.00

Twenty per cent, for engineering and contingencies 3,777,000.00

$22,662,000.00

102

PRESSURE TUNNEL

Size of Tunnel L«ig™ P ,?ff ILB Total Cost

8 feet 0.5 $900,000.00 $450,000.00

Twenty per cent, for engineering and contingencies 90,000.00

$540,000.00

RESERVOIR

One reservoir in Richmond, 400.000,000 gallons dally capacity. . . $750,000.00

Land 300,000.00

$1,050,000.00

Twenty per cent, for engineering and contingencies 210,000.00

$1,260,000.00

Total cost $24,462,000.00

103

REPORT OF COMMITTEE OF BOARD OF ESTIMATE

AND APPORTIONMENT

June-27, 1910.
To the Honorable the Board of Estimate and Apportionment:

Sirs — At the meeting of the Board of Estimate and Ap-
portionment held on March 4, 1910, a Committee, consisting
of the President of the Board of Aldermen, the Comptroller
and the President of the Borough of Manhattan, was appointed
to consider the plans of the Board of Water Supply for the
construction of a pressure tunnel from the proposed Hill View
Reservoir, passing through the Borough of The Bronx, under
the westerly and middle portions of Manhattan Island and
under the East River to the Borough of Brooklyn, and the
said Committee was authorized to retain as expert advisers two
engineers and a geologist, and it was requested to report to the
Board its conclusions as to the feasibility of the project.

Your Committee begs to report that, in accordance with
the authority conferred upon it, it retained Mr. Clemens Her-
schel, hydraulic engineer; Mr. Francis L. Pruyn, consulting
and contracting engineer, and Mr. J. Edmund Woodman, min-
ing geologist. These experts were instructed to advise your
Committee upon the following points:

(1) Is the proposed tunnel practical from an engineering
and geological standpoint?

(2) How does the estimated and probable first cost of this
tunnel compare with (a) the estimated and probable first cost
of a pipe-line from Hill View Reservoir through the Borough
of Queens to Brooklyn, and (b) a pressure tunnel from Hill
View Reservoir through the Borough of Queens to Brooklyn?

(3) Which is the better route for a pressure tunnel, if
constructed, from Hill View Reservoir through Queens to
Brooklyn, or from Hill View Reservoir through Manhattan
Island to Brooklyn?

This Committee of experts, after a careful investigation,
has submitted to us a report reviewing the entire project and
containing a comparison of the cost of the pressure tunnel
under Manhattan Island with the cost of pipe lines, and of a
pressure tunnel through the Borough of Queens, and have

104

given the following answers to the questions submitted to
them :

(1) The proposed Manhattan tunnel is practicable from an
engineering and geological standpoint.

(2) The estimated and probable cost of the Manhattan
pressure tunnel is $26,000,000, and it will require about four
and a quarter years for its construction, while an equivalent
pipe line system is estimated to cost S47.000,000 and to re-
quire about four and a half years for its construction.

Owing to the fact that no borings have yet been made on
the line of a pressure tunnel through the Borough of Queens
to Brooklyn, and owing to lack of detailed information as to
the conditions which w r ould be encountered, comparative esti-
mate of the cost of a pressure tunnel through the Borough of
Manhattan to Brooklyn and one by way of the Borough of
Queens to Brooklyn can scarcely be made, but it is believed
that under equally feasible conditions the Manhattan tunnel
would cost less; that it is capable of supplying all five Bor-
oughs; and that it would not need to be supplemented by a
separate and special pipe line supplying the Borough of Man-
hattan and a cross-connection between Brooklvn and Man-
hattan.

The reply to the third question has already been given in
the replies to Question No. 2, namely, that the route by way
of Manhattan is better than that by way of the Borough of
Queens for a pressure tunnel.

After receiving the report of the experts, your Committee
on June 7, 1910, gave a public hearing to all who wished to
favor or oppose the plan of the Board of Water Supply, and
has also received some briefs accompanied by reports.

In view of all that has been said and written upon this sub-
ject, it seems scarcely necessary for the Committee to review
the various arguments which have been presented. Those op-
posing the plan contend that its cost will be unnecessarily great,
that sufficient information has not been secured, that the esti-
mates of cost are unsatisfactory and unreliable, as are also the
estimates of the future need of water by The City of New
York, while one of the briefs submitted to us suggests a sub-
stitute plan by a tunnel crossing the East River by way of
Rikers Island, a plan which it is estimated by those present-

105

ing it will cost but $18,500,000, while they predict that to
carry out the plan of the Board of Water Supply will probably
cost $56,000,000. These estimates appear to be based wholly
upon speculation with respect to the geological formation, and
do not seem to be predicated upon any accurate information
or scientific investigation.

As to the estimates of cost, your Committee sees no reason
to doubt the reliability of the estimates prepared by the Board
of Water Supply and confirmed by the experts retained by us.
Our confidence in the reliability of these estimates is strength-
ened by the fact that the cost of the work thus far done and
contracted for by the Board of Water Supply has in almost
every instance agreed closely with the estimates made by the
Engineers of that Board.

As to the alleged insufficiency of information which has
been secured, your Committee believes that the preliminary
investigation has been unusually thorough, and can recall but
few great public undertakings which have been characterized
by such thorough and painstaking preliminary study as the
project under discussion.

As to the estimates of the future needs of The City of New
York, they are not the guesses of enthusiasts, but are based
upon years of careful observation and intelligent compilation
of statistics, which can lead to but one conclusion, and that is,
that the Croton watershed has been developed to its ultimate
capacity, and it is only by reason of the fact that the rainfall
for a term of years has been above the normal that the City
has not already seriously felt the need of an increased supply
of water.

It has been urged that there is no occasion for hasty action,
and that no harm will be done if approval of the plans is de-
ferred for the present or until such further investigations can
be made as will unquestionably establish the practicability of
the project. We believe, however, that it would be most un-
wise to postpone action, as it is expected that in about three
years we will have an aqueduct to Hill View Reservoir ready
for the delivery of water, and if at that time there are no means
of distributing it, the City will be unable to avail itself of
the large expenditure which it has made in bringing this addi-
tional supply to the City limits.

106

In conclusion, your Committee is impressed with the fact
that in scientific authority, in the reliability of experienced
engineers and contractors, in careful and unprejudiced analysis,
and in ordinary common sense, the weight of the arguments
we have received is overwhelmingly in favor of the soundness
and economy of the plan of the Board of Water Supply, and
we would recommend that the Board approve of the plan and
profile of the Board of Water Supply dated November 15,
1909, that it direct the Comptroller to issue corporate stock
of The City of New York to an amount not exceeding
$25,000,000 to meet the expense of carrying out the plan, that
the resolution of this Board of January 7, 1910, requesting
the State Water Supply Commission to suspend action on the
said plans, be rescinded, and that the State Water Supply Com-
mission be notified of this action. A resolution to this effect
is herewith submitted. Respectfully,

WM. A. PRENDERGAST,

Comptroller.
JOHN PURROY MITCHEL,

President, Board of Aldermen.
GEORGE McANENY,

President, Borough of Manhattan.

107

BOARD OF ESTIMATE AND APPORTIONMENT CITY

OF NEW YORK

The following was then offered:

Whereas, The Board of Estimate and Apportionment did,
on December 10, 1909, authorize a modification of the general
plan of the Board of Water Supply, said modification contem-
plating the construction of a pressure tunnel under Manhat-
tan Island-, from Hill View Reservoir to the Borough of Brook-
lyn, and by pipe lines leading thence to the Boroughs of
Queens and Richmond; and

Whereas, The Board of Estimate and Apportionment did,
by resolution of December 10, 1909, pursuant to Chapter 56
of the Laws of 1909, being Chapter 54 of the Consolidated
Laws, known as the " State Board and Commission Law,"
request the State Water Supply Commission as speedily as
possible to approve the said modification of the general plan
of the Board of Water Supply; and

Whereas, The Board of Estimate and Apportionment did,
by resolution of January 7, 1910, request the State Water Sup-
ply Commission to suspend action for approval of this modi-
fication until an opportunity might have been had for examina-
tion into the merits of the plan;' and

Whereas, The Board of Estimate and Apportionment did,
by resolution on the 4th day of March, 1910, approve the ap-
pointment of a committee of three with instructions to retain
as expert advisers two engineers and a geologist, and the said
committee was further instructed to examine into the engineer-
ing feasibility of the proposed pressure tunnel, and did report
thereon at the earliest possible moment; and

Whereas, In pursuance of the resolution of March 4, 1910,
a committee consisting of the Comptroller, the President of the
Board of Aldermen and the President of the Borough of Man-
hattan was appointed and did engage the services of two expert
engineers and a geologist, and did examine into the engineer-
ing feasibility of the proposed pressure tunnel, and did also
at 8.30 o'clock on the evening of June 7, 1910, hold, after due
advertisement, at the City Hall, a public hearing, at which
many were heard in opposition to the plan and also many in
favor thereof; and

108

Whereas, The said Committee did, on July 1, 1910, report
in favor of the modification and recommend that the plan be
proceeded with ; now therefore be it

Resolved, That the Board of Estimate and Apportionment
does hereby approve and adopt said report, map, plan and
profile of the Board of Water Supply, dated November 15,
1909, and hereby declares the same to be the final map, plan
or plans, and profile approved and adopted by the Board of
Estimate and Apportionment, pursuant to the provisions of
Chapter 724 of the Laws of 1905, as amended, and that in
order to permit the carrying out of this plan, the Comptroller
is directed to issue corporate stock of The City of New York
in the manner provided by Section 169 of the Greater New
York Charter to an amount not exceeding twenty-five million
dollars ($25,000,000), the proceeds whereof to be applied to
the uses and purposes of the Board of Water Supply ; and be it
further

Resolved, That the resolution of this Board dated January
7, 1910, requesting the State Water Supply Commission to
suspend action on the contemplated modification of the gen-
eral plan of the Board of Water Supply, as set forth in the
resolution of December 10, 1909, of the former Board of Esti-
mate and Apportionment be now rescinded, and that the State
Water Supply Commission be so notified.

Which was adopted by the following vote :

Affirmative — The Mayor, the Comptroller, the President
of the Board of Aldermen and the Presidents of the Boroughs
of Manhattan, Brooklyn, The Bronx, Queens and Richmond
—16.

I hereby certify that the foregoing is a true copy of a
resolution adopted by the Board of Estimate and Apportion-
ment at the meeting of said Board, held on the 1st day of July,
1910.

JOSEPH HAAG,

Secretary.

109

STATE OF NEW YORK

STATE WATER SUPPLY COMMISSION

In the Matter of the Application

of

The City of New York to the State Water Sup-
ply Commission for the approval of the report
of the Board of Water Supply of The City of
New York to the Board of Estimate and Ap-
portionment of The City of New York, dated V r* • •
November 15, 1909, recommending modification
of the map, plan and profile, dated October 9,

1905, approved by said Commission May 14,

1906, which modification is dated November 15,
1909, and is entitled " Board of Water Supply
of The City of New York. Map and profile
showing manner of delivering the water to the
several Boroughs."

On December 16, 1909, the petition in the aforesaid mat-
ter was duly filed with this Commission. The Commission
caused public notice to be given as provided by law that on
the twelfth day of January, 1910, the Commission would con-
duct a public hearing thereon at the office of the Board of
Water Supply of The City of New York. Pursuant to such
notice duly given, the Commission met at the office of the
Board of Water Supply, 299 Broadway, New York City, for
the purpose of such a hearing, noted the appearances, and re-
ceived in evidence such documentary evidence as the applicant
offered.

The Board of Estimate and Apportionment of The City
of New York, by its resolution bearing date January 7, 1910,
requested this Commission " to defer final action on any
projected extensions or modifications of New York's water
supply system. " In compliance with this request and upon
motion of the Corporation Counsel for the petitioner, the
proceedings were adjourned from time to time and until July
13, 1910, prior to which last named date, and on July 1, 1910,

110

the said Board of Estimate and Apportionment of The City
of New York rescinded its resolution of January 7, 1910,
aforesaid. Said Board did by resolution of the same date
approve and adopt the report, map, plan and profile of the
Board of Water Supply dated November 15, 1909, and de-
clared the same to be the final map, plan or plans approved
and adopted by the Board of Estimate and Apportionment pur-
suant to the provisions of Chapter 724 of the Laws of 1905
as amended.

The petition in substance prays for the approval by this
Commission of the plan of the Board of Water Supply of The
City of New York, duly submitted to and approved and
adopted by the Board of Estimate and Apportionment of The
City of New York, for the distribution of the water supply
to be secured from the Catskill Mountain sources to the various
boroughs of The City of New York. The general plan for
the additional water supply for New York City, approved
by this Commission on the fourteenth day of May, 1906, pro-
vided for the construction of storage reservoirs in the Catskill
Mountains and an aqueduct running from such reservoirs to
New York City. It was brought out at that time that the
plans for distribution of the water to the various boroughs
were only tentative and that the same would be covered by a
subsequent application to this Commission. The present peti-
tion, therefore, relates only to an extension or modification
of the original plan for distributing water to various boroughs
of New York City. The proposed plan specifically contem-
plates the distribution by means of a deep pressure tunnel
from Hill View Reservoir through the Boroughs of The Bronx
and Manhattan and extending to Brooklyn, supplemented by
pipe lines to the Boroughs of Queens and Richmond, of the
entire supply of water that may be obtained from the Catskill
sources. In the Borough of Richmond it is proposed to con-
struct a reservoir of four hundred or five hundred million
gallons capacity for local distribution purposes.

The evidence shows that exhaustive studies have been con-
ducted by the engineers for the City to determine the most
feasible and suitable method for the distribution of this Cats-
kill Mountain supply to the various City boroughs. The reports
and data submitted to this Commission bv the Board of Water

Ill

Supply with the petition, together with the evidence given at
the hearing, indicate clearly that the plan proposed, namely,
the pressure tunnel project, is both feasible and economical.
The information at hand and the evidence adduced at the hear-
ings also clearly indicate that the proposed plan is thoroughly
adequate to meet all reasonable needs of The City for a con-
siderable period of time and will result in the least possible
inconvenience to the public and do the least damage to property
during its construction.

It is also shown that the increased pressure which will be
available from the proposed tunnel in some of the districts
to be served will result in a great saving to the City by obviat-
ing the necessity of pumping large amounts of water, which,
under any plan contemplating small pipes, would have to be
pumped in order to afford sufficient pressure for satisfactory
domestic service and fire protection.

The Commission foas made a careful study of the project
proposed, and of the evidence submitted by the petitioner, and
js of the opinion that the proposed plans are both wise and
economical.

It is evident that some proper method for the distribution
of the proposed Catskill Mountain water supply to the various
boroughs of New York City is absolutely essential to the suc-
cessful completion and operation of that proposed system, and
it haying been clearly shown that the proposed plan is both
feasible and economical, this Commission, therefore, finds:

That the plans of the petitioner are justified by public
necessity.

The present petition does not contemplate any action on the
part of The City of New York that will affect in any manner
whatever any other municipality or civil division of the state
or the inhabitants thereof, particular consideration being given
to their present and future necessities for sources of water
supply.

The plan of the City to pay for any and all damages that
may result from the execution of said plans and the acquiring
of any lands that may be necessary therefor is to purchase
the lands and with the money allowed it by the Board of Esti-
mate and Apportionment to pay for such lands and for any
and all damages, whether direct or indirect, that will result
therefrom.

112

The Commission therefore finds and determines:

First — That the plans of the petitioner are justified by
public necessity.

Second — That the plans of the petitioner are just and
equitable to other municipalities and civil divisions of the state
affected thereby, and to the inhabitants thereof, particular con-
sideration being given to their present and future necessities
for sources of water supply.

Third — That the plans of the petitioner make fair and
equitable provisions for the determination and payment of any
and all damages to persons and property, both direct and
indirect, which may result from the execution of the plans
of the petitioner or the acquisition of the lands therefor.

The State Water Supply Commission does therefore grant
the petition and approve the application and plans of the peti-
tioner.

In Witness Whereof, The State Water Supply Commission
hath caused this determination and approval to be signed by
the Commission and caused its official seal to be affixed hereto,
and the same with all maps, plans, surveys and other docu-
ments and papers relating thereto filed in its office in the City
of Albany this 20th day of October, 1910.

HENRY H. PERSONS,

President.
JOHN A. SLEICHER,
[l. s.] MILO M. ACKER,

CHARLES DAVIS,
ROBERT H. FULLER,

Commissioners.

113

STATE OF NEW YORK,

CITY AND COUNTY OF ALBANY ysS "'

I, DAVID R. COOPER, Secretary of the State Water
Supply Commission, State of New York, do hereby certify that
the foregoing is a true copy of original decision in the matter
of the application of The City of New York to the State Water
Supply Commission for the approval of the report of the Board
of Water Supply of The City of New York to the Board of
Estimate and Apportionment of The City of New York,
dated November 15, 1909, recommending modification of the
map, plan and profile, dated October 9, 1905, approved by said
Commission May 14, 1906, which modification is dated No-
vember 15, 1909, and is entitled "Board of Water Supply of
The City of New York. Map and profile showing manner
of delivering the water to the several Boroughs/' duly filed
in the office of said State Water Supply Commission on the
20th day of October, 1910, and remaining on file therein. I
further certify that the said copy has been compared by me
with the original thereof and that the same is a correct tran-
script therefrom and of the whole of said original.

Witness my hand and the seal of said State Water Supply
Commission, this 28th day of October, 1910.

[l. s.] DAVID R. COOPER,

Secretary.

• .** ,

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Canvass of Bids Opened May 16, 1911, for Contract 63, for the Cok

Itbm Dsscbiption Unit Qtjanthi

1 Shaft 1 Linear foot

2 Sinking Shaft 6 in earth •• ••

3 Sinking upper portion of Shaft 8 •• 4 «

4 Sinking lower portion of Shaft S " ••

5 Sinking all shaft* or portions of shafts not in-

cluded in Items U 2, 8 and 4 - " $]

6 Refilling Shaft 1 Linear foot of shaft refilled. . . f

7 Drain tunnel from Shaft 1, complete Linear foot Ml

* Excavation of main and connection tunnels Cubic yard 234,001

9 Additional trimming in shafts and tunnels Square yard 2,001

10 Furnishing structural steel roof support Pound l,350,0t

11 Erecting structural steel roof support " 1,350,011

12 Temporary timbering M f t B. If 501

18 Pumping from shafts and tunnels during con-
struction Million foot-gallons 100,001

14 Drainage channels for shafts and tunnels Linear foot of shafts and tunnels 22,480

15 Forms for outer lining of Shafts 2, 3, 4 and 5. . Linear foot of shaft 706

16 Forms for lining of steel risers Linear foot of riser 560

17 Forms for lining of main tunnels and Shaft 3

connection tunnel Linear foot of tunnel 21,411

18 Concrete masonry in shafts Cubic yard 6,001

19 Concrete masonry in main tunnel and Shaft 8

connection tunnel " " 86,001

20 Excess concrete masonry in shafts and tunnels. . " " 2,006

21 Brick masonry in shafts and tunnels " " 200

22 Dry packing in tunnels " " 6,500

23 Steel interlining in risers Pound 146,001

24 Venturi meter fittings Lump sum

25 Drilling 1%-lnch or smaller holes in rock or

masonry Linear foot 1,006

26 Drilling 1%-inch to 2% -inch holes in rock or

masonry " - 1,606

27 Steel pipe for grouting, etc " " 30,006

28 Miscellaneous plant and equipment for grouting. Lump sum

29 High-pressure air-compressors for grouting Compressor 16

30 Air-stirring grouting machines Machine 5

31 Mechanically-stirring grouting machines Machine i

32 Grouting pads Pad 16

33 Making connections of tank grouting machines to

grout pipes Connection 5,006

34 Setting grouting pads Setting 1,506

35 Sand for grout Ton 3,561

36 Mixing and placing grout Cubic yard 5,010

37 Earth excavation In open cut " " . * 9,006

38 Rock excavation in open cut , " " 4,300

3l9 Refilling and embanking " " 9,661

40 Timber and lumber M ft B. M Iff

41 Concrete masonry in open cut Cubic yard 1.T0J

42 Portland cement Barrel 180,001

43 Steel for reinforcing concrete Pound 70,001

44 Miscellaneous cast iron, wrought iron and steel. . " 12O.0M

45 Galvanizing " 30,001

46 Caring for and setting metal- work furnished by

The City ♦ " 440,00

47 Cast-iron pipe and special pipe castings Ton lj

48 Bronze pipe and miscellaneous bronze Pound 1,0*

49 Vitrified pipe, 15-inch and smaller Linear foot 2.6J

50 Dry rubble masonry and paving Cubio yard H

61 Rubble masonry and paving in mortar " " U

52 Crushed stone and gravel " " 3

53 Section office buildings Lumpsum ....

54 Locker houses Lump sum ....

Amounts of bids,

Time: 40 months Bond required: $800,000 • Awarded contract A — Mason A I
structlon Company, 704-709 Pennsylvania Building, Philadelphia, Pa. D — Pittsburg Contractini
Incorporated, 607 Fifth Ave., New York City G — Bradley Contracting Company, 1 Madison J
York City

FSTKUCTION OF A FOBS
BOBOUGH OF 4

i

•A B i

$335.00
292.00
330.00
310.00

310.00

10.00

45.00

8.30

5.00

.03

.01
60.00

.30

1.26

10.00

4.50

4.00
9.50

6.75
3.00

16.00

2.50

.10

16,000.00

.40

$300.1
250.4
250.
250.4

300.9

15.4
18T.I

8 J
5.4

65

i

8.1
4.0

6
3.

20.1
2.'

1

15,000.4

■i

.60

.20

4,000.00

300.00

300.00

600.00
75.00

1.00
1.50
3.25

5.00

3.00

4.00

.50

65.00

10.00

1.50

.05

.07

.04

6,000.
300.
300.4

300.J
80.6

1.!

*•!

1/

8.
1.
1-

55*.

6.
1.4

.02
100.00

.65
1.26
4.00

5.00

2.25

5,000.00

6,000.00

95.4

• <
3.1

5.

2.
8,600.
3^750.

13,709,373.00 $3,776,568.

or Company, Richmond, Ifl
lpany, Forbes and Jumonv
Now York City H— M*

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Canvass of Bids Opened May 16, 1911, fob Contract 65, fob the Com

Boroughs of Ta

Itbm Description Unit

1 Sinking Shaft 7 in earth Linear foot. .

2 Sinking Shaft 11 " " .,

3 Sinking all shafts or portions of shafts not included in Items

1 and 2 " " .,

4 Excavation of tunnel and drift Cubic yard

5 Additional trimming in shafts, tunnel and drainage drift. . . Square yard

6 Furnishing structural steel roof support Pound

7 Erecting structural steel roof support "

8 Temporary timbering M ft. B. M

9 Pumping from shafts and tunnel during construction Million foot-gallons

10 Drainage channels for shafts, tunnel and drainage drift. . . Linear foot of shafts, tunnel m

drainage drift.

11 Forms for outer lining of all shafts Linear foot of shaft

12 Forms for inner lining of drainage shaft ' "

13 Forms for lining of risers... Linear foot of riser

14 Forms for lining tunnel and drainage drift Linear foot of tunnel and dcIU

15 Concrete masonry in shafts Cubic yard

16 Concrete masonry in tunnel and drainage drift " "

17 Excess concrete masonry in shafts, tunnel and drainage drift "

18 Brick masonry in shafts, tunnel and drainage drift. " "

19 Dry packing in tunnel " "

20 Drainage interlining in drainage shaft Square foot

21 Steel Interlining in risers Pound

22 Steel interlining in and adjacent to drainage drift at Shaft 11 " -

Cutting channels for water stops Square foot

24 Drilling 1%-inch or smaller holes in rock or masonry. . . . Linear foot .

25 Drilling 1% to 2 % -Inch holes in rock or masonry " " .<

26 Steel pipe for grouting, etc " " *

27 Miscellaneous plant and equipment for grouting Lump sum •

28 High-pressure air-compressors for grouting Compressor »

29 Air-stirring grouting machines Machine

30 Mechanically-stirring grouting machines "

31 Grouting pads Pad

82 Making connections of tank grouting machines to grout pipes Connection

38 Setting grouting pads Setting

34 Sand for grout Ton

35 Mixing and placing grout Cubic yard

36 Earth excavation in open cut " "

37 Rock excavation in open cut " "

38 Refilling and embanking " "

39 Timber and lumber M ft B. M

40 Concrete masonry in open cut Cubic yard

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41 Portland cement Barrel

42 Steel for reinforcing concrete Pound

48 Miscellaneous cast iron, wrought iron and steel "

44 Galvanizing

45 Caring for and setting metal- work furnished by The City. . "

46 Cast-iron pipe and special pipe castings Ton ,

47 Miscellaneous gates and valves Gate

48 Bronze pipe and miscellaneous bronze Pound

49 Vitrified pipe (20-inch and smaller) Linear foot.

50 Dry rubble masonry and paving Cubic yard

51 Rubble masonry and paving in mortar " "

52 Pavement Square yard

53 Crushed stone and gravel Cubic yard

54 Reinforced concrete ladders Linear foot.

56 Section office buildings Lump sum .

56 Locker houses

57 Restoration of parks,

«« u

<« «

Amounts of bids,

Time: 42 months Bond required: $900,000 • Awarded contract A — Plttsbur
Boston, Mass. C — Bradley Contracting Company, 1 Madison Ave., New York City D-

Wall St, New Tork City

ction of a pobtion of the clty tunnel of the cats]
onx and Manhattan

:\

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jTJANTTTY

•A

B

C

D

20
435

$400.00
400.00

$225.00
225.00

$421.87
421.87

$400.00
440.00

2,090

310,000

1,500

400.00
7.75
8.00

255.00
9.90
4.50

421.87

11.00

6.00

440.00
10.00
14.00

,400,000

,400,000

600

260,000

.08
.00 ft
60.00
.20

.01

60.00

.80

.03

.01

75.00

.50

.04

.08

100.00

.30

30,950

1.60

1.40

1.80

2.00

2,350

425

850

28,450

18,600

10.00
10.00
10.00
10.00
8.00

7.00
8.00
4.00
2.25
8.00

10.00
10.00
10.00
4.00
10.00

10.00
10.00
10.00
4.00
12.00

120,000

2,000

300

9,000

20,500

8.00

8.00

16.00

3.00

.80

8.00

3.00

18.00

8.00

.35

8.00
3.00
25.00
4.00
1.00

8.00

8.00

16.00

2.60

.80

200,000

60,000

450

1,000

3,000

.06

.06

1.00

.25

.50

.06
.06
2.00
.45
.60

.06
.06
6.00
.50
.50

.10
.10
3.00
.80
.40

40,000

• • • •

14

7
7

.20

6,000.00

200.00

260.00

400.00

.80

4,500.00

850.00

300.00

800.00

.25

5,000.00

600.00

500.00

500.00

.30

10,000.00

250.00

860.00

500.00

50
8,000
2,500
4,000
6,000

12.00

.60

1.00

2.00

1.00

60.00
1.00
1.26
2.00
5.00

100.00
1.00
1.00
2.26
6.00

100.00
3.00
6.00
3.00
9.00

7,200
3,300
5,600
160
2,700

2.00
4.00
1.00
55.00
6.50

2.60

5.00

.75

60.00

8.50

6.00

7.00

.50

76.00

10.00

4.00

5.00

4.00

75.00

15.00

260,000
160,000
115,000
30,000
500,000

1.85
.04
.06
.05
.02

1.46
.04
.08
.05
.02%

1.60
.04
.06
.02
.03

2.00
.06
.10
.03
.07

80

12

8,000

2,000

100

100.00

75.00

.50

1.00

3.00

80.00

100.00

.76

1.50

4.00

100.00

150.00

1.00

2.60

6.00

100.00

1,000.00

1.00

1.50

6.00

100

2,000

300

26

• • • •

3.00
3.00
2.00
2.00
9,000.00

5.00
2.60
2.00
4.00
12,000.00

9.00

4.50

2.00

16.00

10,500.00

6.50

4.00

3.00

12.00

12,000.00

• • • •

• • • •

8,000.00
9.000.00

10,000.00
2,000.00

10,000.00
4,950.00

10.000.00
5,000.00

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|5»580£8540 $5,778,88840 $6,798,819.15

$6^32,100.00 $8,*

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A. Gillespie Company, 60 Caurch St, New York City B~-Tbe Pegu

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the Borough

Itbm Dkscbiptioh Unit i

1 Removing buildings Lump sum .

2 Sinking Shaft 17 in earth Linear foot.

3 Sinking Shaft 18 in earth " " .

4 Sinking Shaft 13 and portions of Shaft 18 in rock

5 Sinking all shafts and portions of shafts not included In

Items 2, 3 and 4 - •• .

8 Excavation of tunnel and drift Cubic yard . ,

7 Additional trimming in shafts, tunnel and drift Square yard

8 Furnishing structural steel roof support Pound

9 Erecting structural steel roof support "

10 Temporary timbering If ft B. If.

11 Pumping from shafts and tunnel during construction Million foot-gallons

12 Drainage channels for shafts, tunnel and drift Linear foot of shaft, tunnel and

drift

18 Forms for outer lining of shafts Linear foot of shaft

14 Forms for outer and inner linings of section valve shafts. . " " " "

15 Forms for lining of steel risers • • Linear foot of riser

18 Forms for lining of tunnel and of drift at 8haft 18 Linear foot of tunnel and drift.

17 Concrete masonry in shafts Cubic yard

18 Concrete masonry in tunnel and drift " "

19 Excess concrete masonry in shafts, tunnel and drift " "

20 Brick masonry in shafts, tunnel and drift M "

21 Dry packing in tunnel and drift

22 Drainage interlining in section valve shafts Square foot

28 Steel interlining in risers Pound ....

24 Steel Interlining in tunnel and at section valves "

25 Cutting channels for water-stops Square foot

28 Drilling lU-inch or smaller holes in rock or masonry Linear foot.

27 Drilling 1%-lnch to 2% -inch holes in rock or masonry. ...

28 Steel pipe for grouting, etc " " .

29 Miscellaneous plant and equipment for grouting Lump sum ,

30 High-pressure air-compressors for grouting Compressor

81 Air-stirring grouting machines Machine . .

32 Mechanically-stirring grouting machines "

33 Grouting pads Pad

34 Making connections of tank grouting machines to grout pipes Connection
36 Setting grouting pads Setting . . .

Sand for grout Ton

37 Mixing and placing grout Cubic yard

38 Earth excavation In open cut " "

39 Rock excavation in open out " "

40 Refilling and embanking

41 Timber and lumber M ft B. M,

42 Concrete masonry In open cut Cubic yard

43 Portland cement Barrel . . .

44 Steel for reinforcing concrete Pound

45 Miscellaneous cast iron, wrought iron and steel "

46 Galvanizing "

47 Caring for and setting metal-work furnished by The City. . "

48 Cast-iron pipe and special pipe castings Ton

49 Bronze pipe and miscellaneous bronze Pound ....

60 Vitrified pipe, 18-inch and smaller Linear foot

51 Dry rubble masonry and paving Cubic yard

62 Rubble masonry and paving in mortar " "

63 Pavement Square yard

64 Crushed stone and gravel Cubic yard

55 Section office buildings Lump sum .

56 Locker houses

57 Restoration of parks.

Amounts of bids,

Time: 52 months Bond required: 8900,000 * Awarded contract A— Grant Smith
42nd St. New York City C — The Degnon Contracting Company, 60 Wall St, New York City
pany, 50 Church St, New York City

DTION OF A PoBTION OF THB ClTY TUNNEL OF THE CaTSKIILL AQUEDUCT IB

v Manhattan

PANT1TY

•A

B

C

D

B

Avxracud

Itbm

• • • •

20

28

405

11,000.00
275.00
275.00
880.00

11,000.00
350.00
360.00
400.00

816,000.00
875.00
375.00
360.00

$10,000.00
603.85
503.85
503.85

$6,000.00
400.00
400.00
500.00

$6,400.00
380.77
880.77
418.77

1
2

8
4

815

330.00

400.00

360.00

503.85

490.00

416.77

6

118,000

1.100

180,000

180,000

325

11.25
5.00

.03

.01 %
70.00

9.75

3.00

.03

.01

50.00

11.60
8.00

.03

.01%
60.00

12.00

6.00

.0ft

.01

75.00

12.60

14.00

.04

.03

100.00

11.42
6.20

.08

.01%
71.00

6
7
8
9
10

100,000

.25

.25

.50

.50

.20

.36

11

24,465

740

840

1,626

2.00

8.00

12.00

6.00

8.00

10.00

7.00

2.00

4.00
4.00
5.00
1.00

1.80
10.00
20.00
10.00

2.00
10.00
10.00
10.00

8.46

8.40

10.80

5.60

12
18
14
15

23,250
9,100

85.000

2.000

200

4.00

10.00

7.60

3.00

25.00

10.00
9.00

10.60
3.00

15.00

4.00
10.00
10.50

8.00
16.00

4.00

10.00

8.00

8.00

25.00

4.00
12.00
10.00

3.00
15.00

5.20

10.20

9.80

3.00

19.20

16
17
18
19
20

6,100
13,600
66,000
56.000

1,600

3.50

1.25

.08

.08

2.00

1.50
.26
.08
.10

1.50

3.00
.80
.08
.08

3.00

4.00

1.00

.06

.06

6.00

2.50
.30
.10
.10

9.00

2.90
.62

.08
.08%
8.10

21
22
28
24
25

1,000

3,000

80,000

• • • •

12

.40

.50

.30

5,000.00

300.00

.40

.60

.26

6,000.00

250.00

.26

.30

.20

6,000.00

250.00

.60

.60

.25

5,000.00

500.00

.80

.40

.80

9,000.00

250.00

.37

.44

.26

6,000.00

310.00

26
27
28
29
80

6

6

40

6,000

2,000

300.00

300.00

80.00

1.76

1.00

360.00

500.00

60.00

2.00

1.00

250.00

200.00

50.00

.60

1.60

600.00

600.00

100.00

1.00

1.00

850.00

500.00

100.00

8.00

6.00

850.00

400.00

78.00

1.67

2.10

81
82
88

84

86

3,600
6,000

12,600
5,000

12,000

1.76
10.00
2.00
4.00
1.00

2.50
2.00
3.00
6.00
1.00

1.50
4.00
2.40
4.50
.60

2.26
5.00
5.00
7.00
.60

3100
9.00
4.00
5.00
4.00

2.20
6.00
3.28
5.30
1.42

86
87
88
89
40

260

2,000

15,000

>0,000

15,000

60.00

8.00

1.40

.05

.07

50.00

7.00

1.36

.04

.06

40.00

10.00

1.80

.06

.07

76.00

10.00

1.60

.08

.05

75.00

16.00

2.00

.06

.10

60.00

10.00

1.68

•SI*

.07

41
42
42
44
45

15.000

)0,000

60

600

4,000

.05

.08

100.00

1.00

1.00

.04

.02 %

100.00

1.00

.50

.02

.06

60.00

.75

1.25

.02

.03

100.00

1.00

2.26

.03

.07

100.00

1.00

1.25

.08

.04

92.00

.95

1.25

46

47
48
49
60

50

150

5,000

400

• • • •

5.00
7.00
5.00
2.50
6,000.00

3.00
5.00
4.00
2.50
3,400.00

4.00
5.00
4.00
2.00
4,000.00

6.00
9.00
4.60
2.00
7,000.00

6.00
6.50
4.00
3.00
8,000.00

4.80
6.50
4.80
2.40
5,480.00

51
62
68

54

65

• • • •
• • • •

8,000.00
10,000.00

10,500.00
10,000.00

6,000.00
10,000.00

7.600.00
6,860.00

7,500.00
5,000.00

7,900.00
8,170.00

66
67

$4,512^0540 $4,719,925.00 $4,961,645.00 $6,028,686.90

$5,050,00540

..and Locher, Rome, N. T. B — The United Engineering and Contracting Company, 17 West
—Bradley Contracting Company, 1 Madison Aye., New York City B— The T. A. Gillespie Com-

1 1

1
t "

J •

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\»I

I .

•

a

» .• (

•; '.. • • >

, . >

4 *

n

1 t. ■

(*•-.

-»♦.

' ,4

t ' ,

i> » . .»

. -i

* i

Canvass of Bids Opened May 16, 1911, for Contract 67, fob the C<

Item

Description

Unit

1
2
8

4
5

6

7

8

9

10

11
12
IS
14
16

21

2*
24
25

26
27
28
29
30

31
82

34
35

37
38
39
40

41
42
48
44
45

46

47
48
49
50

51
52
53
54
56

56
57
58
69
60

61
62
63
64

Removing buildings Lump sum

Excavation of Shaft 19 in earth Linear foot

Excavation of Shaft 20 in earth " " .

Excavation of Shaft 21 in earth " " .

Excavation of Shaft 22 in earth " " .

Excavation of Shaft 28 in earth

Excavation of Shaft 24 in earth

Excavation of Shafts 19, 20 and 22 in rock

Excavation of Shaft 21 in rock

Excavation of upper portions of Shafts 28 and 24 in rock. .

Excavation of lower portions of Shafts 23 and 24 in rock. .

Excavation of tunnels and drifts

Additional trimming in shafts, tunnels and drifts

Furnishing structural steel roof support

Erecting structural steel roof support

<•

Cubic yard ,
Square yard
Pound

16 Temporary timbering ,

17 Pumping from shafts and tunnels during construction.

18 Drainage channels for shafts, tunnels and drifts

19 Forms for outer lining of all shafts

20 Forms for inner lining of drainage shaft,

M ft. B. M ...........

Million foot-gallons ....
Linear foot of shafts, ti
and drifts

Linear foot of shaft -

<« « ]

i

Forms for lining risers ,

Forms for lining tunnels and drifts

Concrete masonry in shafts

Concrete masonry in tunnels and drifts

Excess concrete masonry in shafts, tunnels and drifts.

Linear foot of riser

Linear foot of tunnel and cat
Cubic yard *

Brick masonry in shafts, tunnels and drifts

Dry packing in tunnels and drift

Drainage interlining in drainage shaft

Steel interlining in risers

Steel interlining in and adjacent to drainage drift.

««

n

n

Square foot

Pound

Cutting channels for water stops

Drilling 1%-inch or smaller holes in rock or masonry

Drilling 1%-inch to 2% -inch holes in rock or masonry* • • •

Steel pipe for grouting, etc

Miscellaneous plant and equipment for grouting

High-pressure air-compressors for grouting

Air-stirring grouting machines

Mechanically-stirring grouting machines

Grouting pads

Making connections of tank grouting machines to grout pipes

Square foot
Linear foot

t* M

Lump sum

Compressor
Machine . .

41

Pad

Connection

Setting grouting pads

Sand for grout

Mixing and placing grout.
Excavation in open cut . . ,
Refilling and embanking. .

Setting

Ton

Cubic yard J

<<
<<

Timber and lumber M ft. B. M ,

Concrete masonry in open cut Cubic yard

Portland cement Barrel

Steel for reinforcing concrete Pound

Miscellaneous cast iron, wrought iron and steel "

it

Galvanizing

Caring for and setting metal-work furnished by The City. . " ...

Cast-iron pipe and special pipe castings Ton

Bronze pipe and miscellaneous bronze Pound .

Vitrified pipe, 18-inch to 24-inch, Inclusive Linear foot

Vitrified pipe, 15 -inch and smaller " "

Dry rubble masonry and paving Cubic yard

Rubble masonry and paving in mortar " "

Pavement Square yard

Crushed stone and gravel Cubic yard

Reinforced concrete ladders Linear foot

Section and locker houses Lump sum

Sinking casing and core drilling Linear foot

Casing left in place Pound

Amounts of bids,

Time : 54 months Bond required : $700,000 • Awarded contract A — Holbrc
City B — The United Engineering and Contracting Company, 17 West 42nd St., New Yc
E — The T. A. Gillespie Company, 50 Church St, New York City F — The Degnon Conti
Company, 11 Pine St., New York City

ruction of a portion of the

Bbooklto

Quantity

B

j

42
95
35
93

120
100
1,510
705
215

150

157,000

1,500

1,600,000

1,600,000

290
500,000

24,360

2,900

730

2,350
21,320
26,000
70,000

2,000

200

6,500

36,500

820,000

70,000

475

1,000

3,000

40,000

10
5
5

40
8,000

2,500
4,000
6,000
11,500
4,800

250

3,200

205,000

1,000,000

450,000

45,000

930,000

100

5,000

500

1,200
100
100

5,500
500

50

• • • • •

8,000
5,000

$5,000.00

466.00

471.00

1,082.00

456.00

736.00
614.00
354.00
426.00
423.00

393.00

10.70

4.00

.04

.02%

70.00
.35

2.60
7.60
8.75

2.00

3.75

10.85

10.25

3.00

20.00

2.50

.25

.07

.08

2.50

1.00

2.50

.50

5,000.00

300.00
300.00
350.00
100.00
1.50

1.50
2.00
6.00
3.50
1.00

75.00

12.00

1.50

.07

.06

.06

80.00

.80

2.50

1.25
5.00
6.00
3.00
3.00

2.00

8,000.00

5.00

.06

$1.00

350.00

4&0.00

1,000.00

440.00

750.00
650.00
350.00
400.00
350.00

360.00

10.20

3.00

.04

.01

60.00
.40

8.00

10.00

4.08

2.00
10.00

9.00
11.00

3.00

15.00

2.00

.25

.08

.10

1.50

.40

.50

.26

5.000.00

260.00

350.00

600.00

60.00

2.00

1.00
2.25
4.00
3.00
1.00

50.00

7.00

1.34

.04

.06

.04
.02%
100.00
1.00
.60 j

.45 .
3.00 i
6.00
3.00
2.50

5.00

20,000.00

5.00

.10

$6,272,435.00 $5,295,218.50 I

t and Rollins Corporation, 103 Park Av€

C — J. F. Cogan Company, Contractor

mpany, 60 Wall St, New York City C

■ r

1.

Canvass of Bids Opened Octobee 31, 1911, fob Contract \

Itkm

Description

Unit

Quantity

•A

B

1
2

4
6

6

7

8
9

10

11
12

IS

14
16

16

17

18
19
20

21
22
23
24

25

2S
21

Earth excavation and refilling

Rock excavation

Cast-iron pipe, straight hub-and-

spigot

Cast-iron hub-and-spigot special

castings

Cast-iron flanged pipe and flanged

specials

Cast-iron valve-boxes, manhole
heads and covers

Caring for and setting metal-work
furnished by The City

Structural and reinforcing steel . . .

Miscellaneous cast iron, wrought
iron and steel

Portland cement

Concrete masonry under pavement.

Concrete masonry as cradles for
sewers or drains

Brick or concrete masonry in cham-
bers and sewers

Lead pipe

Crushed stone and gravel

Vitrified or cement pipe, 3 to 8
inches in diameter

Vitrified or cement pipe, 9 to 16
inches in diameter

Asphalt block pavement

Belgian block pavement

Granite block pavement

Macadam pavement

Sheet asphalt pavement

Flag sidewalks and cross-walks. . .

Brick gutter

Cobblestone gutter

•< it

Cubic yard
Ton

Pound
<<

•«
Barrel

Cubic yard

tt ««

«« n

Pound . . .
Cubic yard

Linear foot

tt tt

Square yard

«<
<<
<«
<<

tt

u

Curb Linear foot .

Cement concrete sidewalk Square foot

37,000
200

6,800

220

12

24

240,000
26,000

4,000
660

40

60

280
600

4

160

800

90

6,000

100

4,600

200

400

20

660

100
100

Amounts of bids.

$0.70
4.00

$0.82
2.00

26.40

27.48

66.00

64.00

60.00

65.00

60.00

45.00

.01%
.04

.01
.04

.07
1.66

.04
1.50

10.00

7.00

10.00

4.00

12.00

.16

3.00

8.O0
.20
.01

.60

1.50

1.00

2.00

.36

1.00

1.00

2.00

.30

.30

.70
1.60
.20
.20
.30

.30
3.90

.30

1.00

.30

:!S*

.30
.15

00.00 $24

13.764.04

Time: 12 months Bond required: At least one- third of contract amount * Award

and Thomas P. Murphy. 26th Ave. and Cropsey Ave., Brooklyn, N. Y. C — Joseph Burns, U
Ocean Parkway and Avenue O, Brooklyn, N. Y. F — Cranford Company, 62 Ninth St., Brook
I — Rodgers & Hagerty, Incorporated, 41 Park Row, New York City J — Borough Developmen

FOB THE CONSTKUCTION OF ^

c

D

I

E

$0.95
2.00

$1.27
3.00

$0.75 !
1.15

26.40

25.18

30.35

70.00

67.53

65.00

70.00

56.42

65.00

50.00

56.42

63.00

.02
.04

.02

.05

:°o°« H

.04
1.70

.07%
1.73

.11
1.40

4.00

6.25

3.00 1

4.00

10.00

4.50 j

8.00

.12

1.00

12.00

.20

3.00

9.20 !

.11%;

3.25

.25

.75

1.15

1.00

1.50

.40

.50

1.00

2.20

.50

1.00

1.15 '
3.30

.30 i

.46

.40
2.00
.25
.30
.30

.83
2.00

.60
2.50

.40

.30
2.60

.23
2.30 .

.25 J

.20
.20

.76
.30

.60 ]
.20 j

7,602.50

=3._ ._

$255,685.72 $262,603.60

atract A — F. V. Smith & Son, In4
Bt 125th St, New York City D-
tf. Y. — The Degnon Contracting
apany, .186 Remsen St., Brooklyn, HI

, - i

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'I

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♦ » .:■ • " • •*

■ » •

■' l *» » *

• *•

* i f_'.

•ft

Canvass of Bids Opened August 1, 1911, foe Contract 87, foe the t

Ixnc Dbscbiption Unit Quantity *A

1 Earth excavation and refilling Cable yard 63,000 |1.26

2 Rock excavation " " 2,800 2.00

3 66-inch steel pipe, 36 -inch plate. . . Linear foot 6,840 12.42

4 66-inch steel pipe, 7/ 16-inch plate. " " 11,181 11.38

5 Cast-iron pipe, straight hub-and-

spigot Ton 41 45.00

6 Cast-iron hub-and-spigot special

castings " 26 160.00

7 Cast-iron flanged pipe and flanged

specials " 20 100.00

8 Cast-iron valve boxes, manhole

heads and covers " 60 76.00

9 Steel castings Pound 12,000 •!*

10 Caring for and setting metal-work

furnished by The City " 260,000 .0<tt

11 66-inch Venturi meter Meter 1 2,800.00

12 Structural and reinforcing steel. . . Pound 20,000 - 06

18 Miscellaneous cast iron, wrought

iron and steel " 12,000 •*£

14 Portland cement Barrel 4,200 1-JJ

16 Concrete masonry under pavement. Cubic yard 2,200 *™

16 Concrete masonry as cradles for

sewers or drains " " 660 *> 9Z

17 Brick or concrete masonry in cham- . 1

bers and sewers " " 660 ••Jl

18 Lead pipe Pound 9,000 •**

19 Crushed stone and gravel Cubic yard 10 2.ov

20 Vitrified or cement pipe 8 to 8 a

inches in diameter Linear foot 6,600 - 3y

21 Vitrified or cement pipe 9 to 16 _ A

inches in diameter " " 7,400 °0

22 Belgian block pavement Square yard 400 -J2

23 Granite block pavement " " 200 -U

24 Sandstone block pavement " " 200 -JX

26 Sheet asphalt pavement " " 11,600 I- 50

26 Flag sidewalks and cross-walks. . . " " 1,100 -J2

27 Curb Linear foot 660 -JJ

28 Cement concrete sidewalks Square foot 26,000 * 1V

Amounts

of bids $aee,oH.70 f*»

Time: 11 months Bond required: $200,000 • Awarded contract A ~"Yn wall
Contractors, 280 Broadway, New York City C — The Degnon Contracting Company • <_ f
1942 Forbes St., Pittsburg, Pa. F — Donlon Contracting Co., 84 Broadway, Brooklyn, «. *•

ITBUOTION OF THE BROOKLYN CONDUIT, A PORTION OF CaTSKLLL AQUEDUCT

6 :

c

D

B

F

a

H

Avbbagmb Item

1 |1.60

3.00

16.00

15.00

$1.60

4.00

18.00

17.00

$1.50

4.00

16.50

15.50

$1.50

.01

19.75

19.75

$2.26

7.00

14.75

14.26

$2.71

4.00

19.00

18.00

$1.80

3.75

16.18

15.86

1
2
3
4

I 32.50

30.00

90.00

70.00

150.00

40.00

62.19

5

1 75.00

70.00

125.00

70.00

200.00

100.00

110.00

6

1 80.00

70.00

150.00

70.00

225.00

75.00

112.50

7

f 70.00
1 .09

60.00
.04

80.00
.11

65.00
.07

150.00
.10

55.00
.12%

79.37%
.10

8
9

\ .01%

.01

.06

.02

.04

03%

.03

10

\ 2,500.00
! .03%

2,500.00
.04

2,600.00
.06

4,000.00
.04

2,000.00
.05

3,000.00 .
.04

2,787.50
.04%

11
12

, .05
1.50
4.50

.04
2.00
4.50

.06
1.60
6.00

.05
1.70
5.00

.05
1.60
6.00

.10
1.50
4.50

.06
1.60

4.75

13
14
15

5.00

6.00

8.00

6.50

8.00

8.00

7.06%

16

12.00

.15

1.50

15.00

.10

1.75

10.00

.12

2.50

12.00

.07

1.30

12.00

.16

4.00

10.00

.25

3.00

11.16
.16%
2.63

17
18
19

.16

.20

.90

.36

.30

.65

.46

20

.60
1.20
1.20
1.20
1.25

.50
.50

1.00
.50

2.00

1.50
1.60
1.75
1.75
3.00

1.00
.40
.50
.40

2.00

.75
2.00
2.00
2.00
3.00

1.50
.40
1.00
2.00
1.25

.92
.98
1.22%

1.34%
1.87%

21
22
23
24
25

1.00
.20
.18

1.00
.20
.20

.90
.60
.20

.25
.10
.20

.50
.40
.25

.90
.60
.22%

.87

26

27
28

$441,135.00 $488,267.50

9497,515.00

$519,116.00

$528,735.00

$584,515.00

tovan and Charles Cranford, 186 Remsen St, Brooklyn, N. T. B — J. F. Cogan Company,
jw York City D — James H. Holmes, 87 Nassau St, New York City B — Booth ft Flinn, Limited,
rick McGorern, 6 Beacon St, Boston, Mass. H — Cranford Company, 52 Ninth St, Brooklyn, N. Y.

' /. .

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( • r

• • _'

A-

t •»

I e
< f.

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i * «

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,•.. »

Canvass of Bibs Opened

Item

DB8CBIPTION

Unit

Quait

1
2
3
4

5

6
7
8
9
10

11
12
13
14
15

16
17
18
19
20

21
22
23
24
25

26
27

Earth excavation and refilling ,

Rock excavation

Cast-iron pipe, straight hub-and-spigot. . ,
Cast-iron hub-and-spigot special castings. ,
Cast-iron flanged pipe and flanged specials,

Cubio yard

44 44

Ton

«

i«

Cast-iron valve-boxes, manhole heads and covers

Caring for and setting metal-work furnished by The City

Structural and reinforcing steel

Miscellaneous cast iron, wrought iron and steel

Portland cement

Ton
Pound

44
41

Concrete masonry in pavement foundations

Concrete masonry as cradles for sewers or drains. ,
Brick or concrete masonry in chambers and sewers.

Lead pipe

Crushed stone and gravel

Vitrified or cement pipe 3 to 8 inches in diameter. .
Vitrified or cement pipe 9 to 15 inches in diameter.

Asphalt block pavement

Belgian block pavement

Cobblestone pavement

Barrel . . .
Cubic yard

44 44

41 (4

Pound . . .
Cubic yard

Linear foot

«« 44

Square yard

44

44

Granite block pavement

Macadam pavement

Sheet asphalt pavement

Wood block pavement

Flag sidewalks and cross-walks.

Square yard

44
44
44

44
44
44

Curb

Cement concrete sidewalks,

Linear foot.
Square foot

50,000,
750
8,900
300

10

30

800,000

23,000

4,500

1,200

650

50

300

500

10

800
100
560
50
900

5,700
100

3,900

80

300

250
2,000

Amounts of bids,

Time: 12 months Bond required: $160,000 * Awarded contract A — Beat
tague St, Brooklyn, N. T. E — Cranford Company, 62 9th St, Brooklyn, N. T. F-
Bros., 25th Ave. and Cropsey Ave., Brooklyn, N. T. J — Borough Development* Coi
N. Y. N — The King, Ganey Contracting Company, 120 Broadway, New York City

tBEB

r.v ) -a

*.j- »

•A

::k

fl.20
8.00
16.30
16.00
10.00

19.50

.02

.05

.05
1.50 -

6.60
,0.00
2.00 i

.20
2.50 ,

.50
1.00 i
2.00

.30

.10 .

.90

.30
1.00
8.60

.10 !

.10

I

.20 J
3.00 j

•.».'

c

eerlng

I? r3

O

ft

"i . * i

• ■ A
V

«"..

. (

IV-

• •

'i.'

i. .

'J'. • '

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to
re
a-

,V". *

J-

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te

;ie
d
ie
e

ve

y

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e

P

y

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115

CHARLES P. BERKEY
SUB-STATION 84
NEW YORK CITY

New York, August 1, 1912.

Mr. J. Waldo Smith,

Chief Engineer, Board of Water Supply.

Dear Sir:

In accordance with your request I hand you herewith a
summary of my various reports on the geology of New York
City, with reference to the pressure tunnel plan of the Board
of Water Supply. This summary includes all information to
date and brings together into a brief space all of the more
important data obtained as the result of the extensive explora-
tions which were made in the interest of this public work.

GEOLOGICAL FEATURES OF THE CITY DISTRIBU-
TION TUNNEL

An 18-mile distribution conduit is to be constructed as a
pressure tunnel entirely in rock from the Yonkefs line through
The Bronx and Manhattan to Brooklyn. As soon as this de-
cision was reached, preliminary studies were begun for the
purpose of determining the best location of the line and related
matters. It was appreciated in the beginning that many of the
critical questions were essentially geological in their nature and
would require special attention from that standpoint. The
engineer and the geologist worked alternately on the same
problems until in the opinion of both the best possible line
was .adopted, and the most suitable additional exploratory
work was undertaken. The following pages are written as a
part of the history of the development of this project from the
geologic point of view.

PRELIMINARY STUDIES

Three trial lines were first laid out on a standard street map
of the City from Hill View reservoir just north of the City
boundary to the vicinity of Fort Greene park, Brooklyn. So
far as the general topography and City development and other

116

engineering considerations were then known either of these
three routes could have been used. Special studies, and, if
need be, additional exploratory investigations, were expected
to indicate which would be the most acceptable, and whether or
not it might be advisable to shift even the best one to a still
more favorable location. These original trial lines are shown
on the accompanying map, Sheet 18.

GENERAL CONSIDERATIONS

(1) One of the essential items to be kept in view is that
of length of line. Other things being equal the shorter line
would be preferable.

(2) Another item is depth of tunnel. In general it would
be preferable to avoid the necessity of making an excessively
deep tunnel.

(3) A third is the matter of permanence. This item is
judged to be closely related to the condition of the rock pene-
trated by the tunnel.

(4) Another is relative cost of construction, which is also
in part dependent upon rock quality and rock condition, and
similar factors.

QUESTIONS RAISED IN CONNECTION WITH THE
DISTRIBUTION CONDUIT TRIAL LINES

(1) What rock formations must be* penetrated along each
of the trial lines?

(2) How much of each must be allowed for?

(3) What condition of rock is likely to be found at mod-
erate depth?

(4) Will the rock at moderate depth be such as to permit
successful and economical construction of tunnels to be used
under hydraulic pressure due to Hill View reservoir?

(5) Does the character of the rock in the vicinity of the
lines vary sufficiently to materially affect the cost of a tunnel
if they should be shifted approximately 1,000 feet either way
from their trial location?

(6) Are the suggested locations of conduit lines adapted
from a geological viewpoint to the construction of pressure
tunnel conduits, and, if not, what changes in these lines
would be advisable?

. 117

(7) What depth must be assumed so as to avoid buried
channels, excessive weakness from superficial decay, open
seams, disturbed rock, and weakness due to insufficient rock
cover ?

(8) Are there any special sections along these trial lines
where a moderate amount of exploratory work would help
materially in coming to a decision on choice of line and its
practicability ?

(9) If so, what borings or other form of field exploratory
investigation should be undertaken to determine the location
and practicability of a line for the distribution tunnel?

GEOLOGICAL STUDIES

In large part these original questions depended for their
correct solution on geological data. In fact, they required
more detail and greater accuracy than was then available in
the published reports and maps of the Greater New York area.
It was necessary to determine the following points more accu-
rately :

(a) The contacts between formations, especially where
a line was drawn parallel to and near the edge of a formational
boundary.

(b) Variation in the quality of rock in each formation.

(c) Any unusual structural conditions, such as fault zones
or excessive jointing or interbedding.

(d) The exact location of special conditions that would in
any way materially affect construction and form an essential
item in the specifications and plans.

In accord with these requirements a thorough geological
study was begun covering every item that seemed to have a
bearing on such engineering questions. The whole immediate
region was mapped in enough detail to locate all outcrops of
ledges within 1,000 fe'et of the trial lines, as much accuracy as
possible was given to the boundaries of formations, and special
attention was given to all surficial evidences of unusual under-
ground conditions. The following is a general statement of
the essential features of local geology that have proved to be
dependable in these studies.

118

Geological Formations

There are six local formations* coming within reach of
these lines of sufficient permanence and individuality and areal
importance to be treated as units in this study.

They are the Glacial drift, Manhattan schist, Inwood lime-
stone, Fordham gneiss, including two large intrusive members,
Yonkers gneiss and Ravenswood grano-diorite.

THE GLACIAL DRIFT

Only rarely is there any residuary soil left undisturbed by
glaciation. Everywhere there is glacial drift of varying thick-
ness through which project small portions of rock ledges as
outcrops. There is almost always an abrupt break between the
bed-rock and the loose drift, and the constituents of the drift
differ materially from those of the rock floor. Worn boulders
are common and in some cases their original sources are readily
traced by the character of the rock. The bed-rock is generally
smoothed and grooved in such manner as to indicate the direc-
tion of glacial movement which is about South 30° East.
Therefore it is not at all unusual to find abundant boulders of
Palisade trap carried from the west side of the Hudson, mixed
into the drift mass. Occasional boulders are clearly identical
with ledges to be found in the Highlands, or the Catskill and
Helderburg regions, or still farther away.

The drift varies in thickness to more than 200 feet within
the City. It is thickest in narrow valleys where, in some cases,
the original contour is wholly obscured and an entirely new
topography is developed on the drift. These buried valleys
or other rock floor depressions usually require special explora-
torv investigation to determine data with sufficient accuracy
for engineering uses.

There are in this district two fundamentally different types
of drift as to method of deposition. They are fa) unassorted
drift, usually called " till " or " hard-pan/' and (b) modified
drift, which is simply assorted or partially sorted drift mate-

* A more comprehensive description of the local formations may be found
in the Proceedings of the Municipal Engineers of The Citv of New York for 1911
under the title: '"The Geology of New York Citv and its "Relation to Engineering
Problems.'* A still more extensive discussion of the geology of the surrounding
region may be found in Bulletin 146. N. Y. State Museum, Fart I. A good
geological map and accompanying explanatory text on the geology of New York
City is issued by the U. S. Geological Survey as Folio No. 83.

119

rial such as gravels, sands, silts, clays. The former (a) repre-
sents deposition directly from the ice at its margin or beneath
the ice mass without enough water action to rework or assort
the material. It therefore contains boulders, pebbles, gravel,
sand and clay, all mixed together in a most complex way.
Such ground is almost always compact and rather impervious
in comparison to the other type. Till and assorted materials
are commonly closely associated. It often happens that one
type passes rather suddenly into the other laterally, or that
one type lies beneath the other at the same point.

The modified drift of the district has in the process of its
accumulation suffered chiefly a separation of the fine from the
coarse particles. In most cases the fine matters that help to
make till dense and impervious has been washed out and
deposited elsewhere in standing waters as silt and clay. As a
result, most modified drift deposits are made up largely of
sands and gravels, are very pervious, and carry great quan-
tities of water. Such deposits furnish the building sands of the
New York market, such as " Cow Bay sand."

Modified drift is generally readily penetrated by simple
exploratory wash boring equipment, while till is usually
troublesome because of the occurrence in it of random boulders.

The accumulation of drift material represents a rather com-
plex process with advance and retreat of the ice and with
variable assorting action, so that in most of the thicker de-
posits both types occur. Explorations should show how much
of it is till and how much is modified drift.

MANHATTAN SCHIST

This is primarily a recrystallized sediment of siliceous type.
It occurs as a nearly black or streaked, micaceous, coarsely
crystalline, strongly foliated rock. The chief constituents are
biotite, muscovite and quartz. Feldspar, garnet, fibrolite and
epidote also occur in large quantity. Occasional streaks or
masses are hornblendic instead of micaceous. Pegmatite veins
and lenses and dykes are also extremely common in some local-
ities, making up a considerable proportion of the formation.
They are of igneous and aquseo-igneous origin.

It is essentially a quartz-mica schist. But it is almost
everywhere very coarse textured and hardly ever exhibits the

120

fine grained, uniform structure of typical schist. Its abnormal
make-up — the predominance of biotite and quartz — is the best
defense for its petrographic classification. The abundance of
mica makes it a tough rock but not very hard. Joints and
fractures formed in later movements are not healed and zones
of bad shattering are susceptible to considerable decay. These
crushings are sufficiently common to encourage borings to tap
their content of water for small family use in suburban dis-
tricts; but they do not represent large circulation in any case,
On the whole, the rock if fresh is good and durable. It may,
though rarely, carry considerable sulphide. Practically all of
the strictly original sedimentation marks are destroyed by meta-
morphism. The formation has great thickness, but because of
the destruction of original bedding lines by recrystallization
and additional complication by most complex folding, shear-
ing, crushing and faulting, the structure can not fully be un-
raveled and the thickness can not be estimated with any ap-
proach to accuracy of detail. But there is probably a thickness
represented of several thousand feet.

This is the principal bed-rock formation of Manhattan
island.

INWOOD LIMESTONE

Inwood limestone or dolomite. This formation lies beneath
the Manhattan. It is everywhere coarsely crystalline
either massive or strongly bedded, often very impure with
development of secondary (recrystallized) mica (phlogopite)
and other silicates, especially tremolite. It is essentially a
magnesian limestone or dolomite in composition. There is
an occasional quartzose bed in the midst of the limestone.
The upper beds are most charged with mica and occasionally
beds attacked by alteration have much green, flaky chlorite.
There are occasional interbeddings of limestone and schist as
a transition facies.

The coarser grades upon exposure to weathering readily
yield by disintegration to a lime (calcite) sand resembling
roughly an ordinary sand in general appearance. At Inwood.
the type locality, this disintegration is so pronounced that
great quantities are readily shoveled up and used for various
structural purposes in the place of other sand. This dolomite
is especially liable, as now shown by extensive explorations, to

121

serious decay to great depth. The underground circulation
seems to attack the micaceous beds with great success and in
some places the residue after this solvent action is of the con-
sistency of mud. A nearly vertical attitude of the beds no
doubt encourages such action.

The thickness probably varies, but in many places where
there is only a narrow limestone belt it is due more to shear-
ing or faulting out than to original thinning. The most satis-
factory estimates are based on the explorations at the Harlem
river. They indicate an approximate thickness of 750 feet.
But in all cases either the margins are obscured or there is
possibility of faulting to modify measurements. There are no
fossils. Weathering and erosion has almost everywhere devel-
oped valleys or depressions especially small tributary valleys
in all formations, but as pointed out years ago by Professor
Dana the principal valleys prevailingly coincide with the lime-
stone belts.

FORDHAM GNEISS

The lowest and oldest, as well as the most complex in struc-
ture of all the rock formations is essentially a series of
gneisses. Cutting these gneisses as intrusions of various forms
are a number of more or less distinctly igneous types. They
range in form from small dykes to large batholithic masses,
and in composition from acid pegmatites and granites to
medium basic diorites. The pegmatites are numerous and
abundant but they are nowhere of sufficient prominence to
be regarded as a distinct formation. Two of the igneous in-
trusions, however, are strongly developed within the City and
in certain localities occur to the exclusion of all other members.
These deserve separate treatment in work of this kind because
they have very characteristic qualities of behavior. These
two special members are known locally as the Yonkers gneiss,
and the Ravenswood grano-diorite.

As intrusives, of course, they are both younger than the
complex series of metamorphosed beds into which they are
injected.

The older portion — always referred to locally as the
Fordham gneiss proper — consists of a series of banded gneisses
of various sorts and a variety of interbedded schists, quartz-
ites, and limestones — all together forming the metamorphic

122

basal complex at the bottom of the geologic column in this
district. It was originally a series of sedimentary beds. There
is nothing known here that is older. It is regarded by geolo-
gists as the equivalent of the Grenville series of the Adiron-
dacks and Canada.

No single type and no single characteristic can be given as
a simple guide to the identification of this formation. The
prevalence of certain varieties or groups of these and the
strongly banded structure give a certain degree of character
that forms a reasonable working basis. The formation in-
cludes banded granitic, hornblendic, micaceous and quartzose
gneisses ; mica, hornblende, chlorite, quartz and epidote schists ;
garnetiferous, pyritiferous, graphitic, pyroxenic, tremolitic,
and serpentinous limestones, ophi-dolomites, serpentines and
quartzites. This is the basal series. But it is complicated by
a multitude of bands of granitic and dioritic gneisses that repre- '
sent injections of igneous material at a time sufficiently remote
to be subjected to most of the early metamorphic modifications.
The equally abundant occurrences of quartz stringers and peg-
matite lenses, though of later origin, can not be separated
from this complex mass, and the whole must be regarded as a
physical unit. The occurrence of interbedded limestones and
quartzites together with a variety of comformable schists and
banded rocks, marks the formation as essentially an old re-
crystallized sediment.

No member of this older unit of the basal complex is suf-
ficiently prominent to indicate a great break or change up to
the time of the first great dynamic movements and igneous
outbreaks. The following comparatively constant members
are sometimes persistent enough to be considered formational
units, but even more commonly are obscure as to boundaries
or are of too small development to map separately.

(a) Banded Gneiss. Granitic and quartzose black and
white banded gneisses and schists of very complex composition
and structure. Regarded as the "typical Fordham."

(b) Interbedded Quartzite. Always a quartzite schist and
always exhibiting conformity with the banded gneisses and
schists. This is regarded as probably the uppermost member.

(c) Interbedded Limestones. Crystalline. Interbedded,
very impure, serpentinous and tremolitic, granular dolomites,

123

usually 2 to 50 feet thick, possibly reaching a thickness of
more than 100 feet in a few cases.

(d) Older Intrusives. Variable types, mostly gneissoid
granites or diorites.

Many are of very obscure relations. The line of close dis-
tinction between recrystallized sediment, segregations accom-
panying that change, and true igneous injection can not be
drawn.

THE YONKERS GNEISS

This is a biotite granite in composition but with a distinct
foliation shown especially by the mica flakes. It is therefore
because of the structure, to be classified either as a granite
gneiss or a gneissoid granite, dependent upon the origin of
the foliation. This is commonly regarded as a metamorphic
effect and the rock is accordingly called a gneiss — Yonkers
gneiss as a locality designation because of its large develop-
ment in the Yonkers district.

It is a rock of very granular habit, with an abundance of
quartz and microline and disintegrates under weathering to a
residuary sand. It is light colored, usually light pink, and
rather uniformly foliated but not at all banded and rarely
streaked. It is of fairly uniform quality and is regarded as a
good type of rock unless excessively weathered.

THE RAVENS WOOD GRANO-DIORITE

This is another intrusive of similar origin and age as the
Yonkers gneiss. But it is more variable. It is generally
slightly foliated and carries enough basic, dark colored, mineral
constituents to present a grayish color even in the more acid
varieties. The mineral variation is considerable — some
varieties having the mineral proportions of a typical granite —
others of a typical diorite, and there are all gradations between.
For this reason largely it is called a grano-diorite. At the
time of its intrusion, large blocks of the older banded gneiss
(Fordham proper) and associated layers were partially
digested (fused) into the igneous mass. Occasional traces of
such blocks can be seen in the grano-diorite and still more
commonly such fusion is indicated by certain abnormal min-
erals such as an abundance of garnet m the grano-diorite. Its

124

most typical development is in Long Island City and in Ravens-
wood, from which its gets its local name.

This formation is one of the most substantial in the City.

It was found that in New York City the six above described
formations were sufficient basis for mapping along the con-
duit lines, in both the preliminary and the final studies.

Structural Features

These old rock formations, constituting the floor of New
York City, are complicated by folding and faulting and igneous
intrusion and metamorphism to such extent that in some places
these conditions are more important than the identity of the
rock itself. It has been necessary to make detailed cross-sec-
tions of certain localities showing these structures. The places
requiring extra exploration have all been of more complicated
structure than usual. For a working understanding of the local
geology it is necessary particularly to appreciate the character
of folding and faulting in the district.

FOLDS

The folds of the ancient rock floor formations are compli-
cated and variable and sometimes obscure. Everywhere the
Manhattan schist and Inwood limestone and Fordham gneiss
occur in strips lying more or less persistently parallel with each
other. A strip of Inwood limestone a few hundred feet wide is
usually bounded on one side by Fordham gneiss and on the
other by Manhattan schist. This succession is repeated so often
that there is no doubt whatever that it is of the normal order.
But also the formations almost everywhere indicate that they
are highly tilted and often actually stand on edge. They were not
originally deposited in this position, but have been subsequently
forced into such position by lateral thrusts which crumpled the
beds together into a series of folds. Long continued erosion, ages
ago, removed the most exposed portion, and only the stumps
of the original folds remain. Therefore, each strip of lime-
stone marks the limb of a fold as it comes to the surface, and
one should be able to reconstruct the curve that it used to
make, now an imaginary arch in the air coming down and
passing below the surface again over beyond the adjacent

125

ridge of gneiss. One may follow the beds as they extend
down some hundreds or thousands of feet below the surface,
until turning upward again on the other side of the trough
they finally reach the surface as in the first case. The whole
proceeding is neither obscure nor difficult, and it is an abso-
lutely necessary step to take if one wishes a working under-
standing of the structural relations of these older formations.
A little careful observation will then convince one that the
formation found within the limestone arches is always Ford-
ham gneiss, and that the formation found within the limestone
troughs is always Manhattan schist. Such distribution and
relation can have only one meaning, i. e., the Fordham is the
basal and oldest member of the series. Wherever Manhattan
schist is the surface formation one can find the Inwood lime-
stone and Fordham gneiss below if only the exploration be
carried deep enough. On the other hand, no matter how deep
the Fordham gneiss is penetrated no other formation has yet
been found beneath. Folding so closely repeated, such as is
exhibited in these rocks, is never perfectly symmetrical. In
New York City, sometimes the beds are tilted even beyond
the vertical (overturned). If locally they seem to be very
differently related, knowing the standard succession, there need
be no difficulty at all in detecting the occurrence as abnormal.
There are no flat-lying beds. Large areas of a single forma-
tion, such as of schist in the eastern portion of The Bronx or
in western Manhattan, means that the crests of the underlying
limestone and gneiss do not reach to the surface and conse-
quently the whole surface is schist. But structurally the schist
of those areas is folded into troughs and arches just as system-
atically as are the formations where the whole series is exposed.
The series of folds has been formed by thrusts that seem to
have acted from the southeast, and consequently the axes of
thef folds trend northeast and southwest. All of the belts or
strips of these formations, therefore, also have the same trend.
Furthermore, the axes of the folds pitch slightly to the south-
west, so that the tendency is for the older formations to pass
beneath the surface southward.

If one follows a particular ridge of gneiss from north to
south it will generally be found that it becomes gradually
narrower and lower till it finally passes beneath the limestone

126

and this in turn passes beneath the Manhattan schist. All of
these folds are old — older than the folding of the Appalachian
mountains.

FAULTS

An additional source of complexity lies in the fracturing
and displacement of two portions of a formation which origi-
nally lay immediately adjacent. This is known as faulting.
When this occurs the regular succession may be abruptly
changed. In some instances a whole formation is cut out, and
two that normally do not belong together are brought into con-
tact. Such an effect is brought about between Blackwell's isl-
and and Manhattan, where a tunnel at 72nd street shows that
Manhattan schist lies in contact with Fordham gneiss. Most
of the known faults have taken place along breaks that trend
northeasterly with the structure, but others running north-
westerly across the formational structure are also well
known. Fault planes are places of weakness which, if not re-
healed by deposition or recrystallization, become the principal
courses of water circulation. This has a double bearing. It
marks out the places where deeper decay than usual is to be
found, and it also marks the chief source of water-supply for
wells drilled into the crystalline rock.

Both folding and faulting have taken place in different geo-
logic periods. In the case of faults, the older ones are more
likely to be rehealed and to be about as impervious and durable
as any other portion of the rock, while the latest ones are
usually not healed and their broken or open character encour-
ages circulation and consequent solution and decay effects.

The greatest of the local faults is probably that following
the course of the Hudson river. The west side of the Hud-
son is apparently dropped down with respect to the east side.
The position of the fault is such as to defy direct observation,
but general regional relations favor its existence.

A fault that has developed much broken rock by its move-
ment and that is not rehealed completely is called a " crush
zone." It is a zone of excessive weakness as a rule — in part,
because the rock is broken and in part because there is in-
creased water circulation and generally much decav.

127

UNCONFORMITIES

Between the Manhattan schist and Inwood limestone there
is no time break. The beds follow one upon the other in
normal order. But between the Fordham gneiss and the In-
wood limestone there may be more of. an interval. The lime-
stone does not always lie next to the same beds of gneiss. This
leads to the belief that these two formations are not perfectly
conformable.

PHYSIOGRAPHIC HISTORY

Present surface features are everywhere the result of the
orderly work of a few well-known geologic agencies acting
on the combination of formations that in the vicissitudes of
past geologic time have been developed as the rock floor of a
region. The agencies of most consequence are the atmosphere,
surface heat, water and internal forces. The activities of most
importance are atmospheric weathering, changes of tempera-
ture, wind action, the erosive action and transportation work
of water, and shifting of levels caused by internal dynamic
forces. Different regions have back of them a different his-
tory which is preserved permanently in the condition and rela-
tions and structures of its rock floor formations, and, however
long and persistently the agencies of erosion may work, the
resulting relief will always be consistent with these factors.
On the other hand, if one knew all of the niceties of relief
character that could arise from every variety of rock and rock
structure, it ought to be possible to work backwards and inter-
pret underground conditions from the physiographic features
of the surface alone.

For New York City and adjacent districts the starting point
of the present surface form dates back to Cretaceous time. The
continent stood then for an exceedingly long time only mod-
erately elevated above sea-level, and remained stable so long
that nearly everything was worn down to a simple plain of
erosion so very flat that it is always referred to as the " Cre-
taceous peneplain." On the divides between the greater stream
courses of that time, of course, there were occasional areas
that had not yet been worn down to the general level. These
patches were either of harder rock type or so distant from the
best channels of erosion that they lagged behind in the general

128

reduction of surface. Such an area represented the present
Catskill mountains. But none of our present-day relief fea-
tures about New York City were in existence, except potenti-
ally in the differences of structure of the rock floor of that
time. That ancient plain existed somewhat above the level
of the average elevation of the tops of our highest hills in south-
eastern New York. This plain drained into the Atlantic, where
the waste that the streams carried accumulated as Cretaceous
sands and shales. As a whole it must have reached present sea-
level at about the East river and the Upper bay and must have
risen gradually inland for several hundred miles. The streams
flowed sluggishly over silts and sands and heavy residuary soil
which obscured the rock floor everywhere. The underlying
rocks, therefore, had no control of the stream courses as they
flowed on the alluvial deposits there.

But at the close of Cretaceous time the whole continental
margin was elevated at least several hundred feet, perhaps in-
land as much as 2,000 feet, above its former level and warped
and tilted somewhat unevenly toward the sea. Then the work
of erosion was actively renewed (.rejuvenated).

All of the relief that we now see has been carved out of that
old plain by the erosive activity of the streams and other sur-
face agencies since that time. Portions that now form the hill-
tops and mountain tops of this district and adjacent ones were
in the beginning of this epoch constituent parts of the rock
floor of the peneplain. As soon as streams had cut down
through their alluvium to bed-rock again and this obscuring
mantle was removed, they began to lay out the lines on which
present-day relief has been developed. The making of valleys
may be considered the primary work of a stream. This is ac-
complished by removing the disintegrating rock and soil as it is
formed on the rock floor. Where no such disintegration is
taking place little work can be done ; wherever decay is rapid
there it is also possible for much work to be done by the
stream, and by the removal of debris the beginnings of a valley
are made. Thus it happens that streams have great facility
in finding and following the softest or most easily attacked lines
or zones or belts or formations — a fact that is of immense prac-
tical value to the geologist and engineer. Their distribution
is studied with great care. They furnish clews to weaknesses

129

or other structures that are too obscure for any other agency
to find. In the course of time, after the main streams and
tributaries have had opportunity to discover the easiest lines,
the structure of the rock floor of a region like New York is
indicated by them almost as clearly as the lines of a geological
map.

When the continent was elevated at the close of Cretaceous
time and streams were rejuvenated and valley-making began
anew, the streams that were already in existence on the old
peneplain surface soon removed the alluvium that covered the
rock floor and discovered a rock structure inconsistent with the
courses they then had. Some of the master streams were large
enough to establish channels that kept them in their original
courses, in spite of the fact that later they found themselves
crossing hard and soft, very resistant and very easily destroyed
formations. Such behavior is credited to the Hudson. But
most of the tributary or smaller streams of all kinds shifted
into the prevalent structural lines. The hard and soft beds,
the trend of folds, the strike of strata, the position of fault
zones, the areas of harder igneous or crystalline rock were dis-
covered. Valleys were made where the softer ones are, ridges
were left where the harder ones are, and surface relief took
on the beginnings of present-day lines. Only the hills were
not so high above the valleys, because the valleys were not
yet cut so deep below the level of the old peneplain. As would
be expected, the main ridges in the areas of the older crystal-
line rocks, including the Manhattan-Inwood-Fordham series,
developed rounded outline and a trend northeast and southwest
parallel to their structure. In the Triassic rocks on the west
side of the Hudson there came to be prevalent a series of east-
ward facing cliffs surmounted by the very uniform ridges that
gradually die away to the westward in gentle dip slopes only to
be succeeded by still others of similar form, a form that is ac-
centuated wherever igneous intrusions occur. The lower
Hudson exhibits such character. In the Cretaceous and Terti-
ary strata of Long Island the steeper sides face northward
and the gentler slopes are toward the sea. Long Island Sound
valley, which is now simply drowned, is one of this type. Trie
northern margin of Long Island constitutes a steeper north-
ward facing slope while the gentle southern slope reaches to
the sea.

130

If the continent were to stand stable for long enough time
the whole region would once more be worn down to another
and lower peneplain. The tendency would be for the large
streams, which work rapidly, to cut down their valleys to ap-
proximately the final level first. Additional work then widens
them into flat-bottomed valleys which, by further widening and
extension, mark out the new peneplain position with consider-
able definiteness. The position of it below the original Cretace-
ous peneplain would depend upon the elevation of the continent
above the sea. At least one such level was marked out in Ter-
tiary time. The continent stood somewhat lower than now.
The streams reached grade and began developing wide flat-
bottom valleys marking out the new peneplain. But before it
was a third finished a second elevation affected the region, the
whole continental border was raised a few hundred feet and
again warped or tilted seaward, the streams were rejuvenated
and began to cut notches into the bottoms of their flat-bottomed
valleys, making valleys within valleys everywhere.

These processes and principles are the keys to an under-
standing of local surface features. The rock floor in New
York is a surface developed in this way. It has a form per-
fectly consistent with such stages of history, such selective
activity of erosion agents and such structural control. Its
most perfect development had been reached in Pleistocene
time, just preceding the Ice age.

But just before the glacial occupation the continent was
again greatly elevated, the largest streams cut deep, narrow
gorges, which were incomplete when the continental glacier
began to cover it. The ice scraped off the exposed promin-
ences, plowed up the residuary soil, carried in immense quanti-
ties of waste rock from more northerly areas, and finally with-
drew leaving the mixed lot choking the valleys, obscuring the
escarpments and covering most of the rock floor. It has done
three things that modify the perfect stream erosion topography
that had previously been developed, (a) It removed much
loose soil, (b) it gouged out or broke off a good deal of more
substantial rock, actually widening and deepening some of the
gorges and valleys wherever their courses encouraged ice flow,
and (c) it has piled up glacial drift in such a promiscuous way
that manv of the finer relief lines are obscured.

131

THE GEOLOGIC MAP

The areal distribution of geological formations along the
proposed lines in New York City has been shown on the ac-
companying map (Sheet 18). Outcrops are shown in solid
colors and the estimated extent of formations is indicated by
line patterns of different colors.

In general the kind of rock to be found at tunnel depth will
be the same as at the surface, as indicated on the map for each
point. Such error as there is arises from these two causes:
(a) Uncertainty about the exact position of the contact lines
between formations along certain stretches of ground (usually
due to heavy drift cover), and (b) the dip and pitch of the
rock.

In the first case (a) where the drift is particularly heavy,
it is sometimes impossible to fix a contact line accurately from
surface features alone.

In the second case (b) it must be appreciated that nearly
all of the formations dip eastward at a very steep angle, so
that a formation would usuallv be found to extend a little fur-
ther east at depth than at the surface. And also all formations
pitch southward, so that they would be found to extend con-
siderably further south at depth than their surface outcrops.
This angle of pitch is from 10 degrees to 30 degrees.

Tn nearly all these cases, however, the obscurity of the
actual surface boundaries is as great a source of uncertainty as
the effect of dip and pitch, so that the boundaries as mapped
may be considered sufficiently accurate for this comparative
study of the lines.

It is worth noting that the rock at the proposed depths of
tunnels would be, as a rule, more substantial than at the
surface. But there are several places on all of the lines where
the exact condition is unknown at the surface as well as at
depth. The chief points of this character will be noted in a
later paragraph.

SPECIAL COMPARATIVE STUDY OF THE TRIAL

LINES

A comparison of the three lines submitted as the basis of
examination — (a) the westerly one, (b) the central one,
(c) the easterly one (see accompanying map, Sheet 18), as

132

to rock formations likely to be cut by them, furnishes the
following figures:

Line A — Going Southward from Hill View Reservoir

6,200 fee

1,400 fee

1,400 fee

5,600 fee

2,400 fee

1,600 fee

4,000 fee

800 fee

16,400 fee

2,000 fee

4,200 fee

12,800 fee

21,000 fee

6,000 feet—

Yonkers gneiss — good rock.

Fordham gneiss.

Probably largely In wood limestone with one
weak zone (at Van Cortlandt lake).

Fordham gneiss — good rock.

Near contact with limestone, probably in gneiss.

Crossing Harlem river — Inwood limestone.

-Inwood limestone — probably fairly good rock.

-Inwood limestone — probably containing bad
zone to Speedway.

Manhattan schist (to 135th street).

■Along contact between schist and limestone.

Inwood limestone with one weak zone (to south
end of Morningside park).

Manhattan schist — probably good quality (to
south end of Central park).

■From Central park to East river — no outcrops —
mostly Manhattan schists at tunnel depth.
Condition largely conjectural — probably
mostly good rock with occasional weak zones.

Manhattan island to City Hall, Brooklyn — Con-
taining an unknown zone in the East river
and unknown quality of rock in Brooklyn.

SUMMARY OF LINE A

6,200 feet — Yonkers gneiss.

7,000 feet — Fordham gneiss.

2,400 feet — Contact (probably in gneiss).
12,000 feet — Inwood limestone.

2,000 feet — Contact (probably in limestone).
29,200 feet— Manhattan schist (good).
21,000 feet— Estimated Manhattan schist (fair)

6,000 feet — Almost unknown.
85,800 feet— Total.

133
Line B — Going Southward from Hill View Reservoir

8,000 feet — Yonkers gneiss — good quality.
13,000 feet — Fordham gneiss — good quality.
6,800 feet — Inwood limestone — probably mostly in fair con-
dition, except at two points (to Cromwell
avenue).
6,600 feet — Inwood limestone — unknown condition, but

probably largely poor (to Harlem river).
600 feet — Inwood limestone — unknown condition (Harlem

river).
4,600 feet — Inwood limestone — unknown condition — proba-
bly fair (to Mount Morris park).
800 feet — Manhattan schist — good quality.
800 feet — Probably Manhattan schist — unknown quality.
2,800 feet — Inwood limestone — unknown condition — proba-
bly at least one bad zone (to 106th street).
12,000 feet — Manhattan schist along Central park — good.
8,600 feet — To Broadway — Manhattan schist (little known

except from tunnels already made).
14,000 feet — To East river — probably Manhattan schist (same

as Line A).
6,000 feet — Manhattan island to City Hall, Brooklyn — un-
certain condition (same as on Line A).

SUMMARY OF LINE B

8,000 feet — Yonkers gneiss — good quality.
13,000 feet — Fordham gneiss — good quality.
21,400 feet — Inwood limestone — variable quality.
12,800 feet — Manhattan schist — good quality.
23,400 feet — Estimated Manhattan schist — fair.

6,000 feet — Almost unknown.
84,600 feet— Total.

Line C — Going South from Hill View Reservoir

6,000 feet — Yonkers gneiss — good rock.

17,400 feet — To Webster avenue — Fordham gneiss — good

rock.

134

5,000 feet— -Along contact between limestone and gneiss.

9,800 feet — To 138th street — Inwood limestone with proba-
bly two bad zones,

1,800 feet — To Bronx kills — along contact between limestone

and gneiss — uncertain quality.
600 feet — Across Bronx kills — mostly in limestones con-
taining a fault zone — probably bad ground.

6,400 feet — Crossing Randall's and Ward's islands and Little

Hell Gate — nearly all is Manhattan schist of
good quality.

1,000 feet — Crossing Hell Gate — Inwood limestone.

1,200 feet — Crossing Hell Gate — Fordham gneiss of good

quality.

1,800 feet — Astoria point — probably Fordham gneiss of good

quality.

1,000 feet — Crossing another limestone belt.

1,000 feet — To Vernon avenue — Fordham gneiss of un-
known quality containing one fault zone.

7,000 feet — To Nott avenue — Ravenswood grano-diorite —

good rock.

2,800 feet — To Borden avenue — probably Ravenswood

grano-diorite.
18,400 feet — To Fort Greene park, Brooklyn — almost wholly

unknown but probably contains 5,000 or 6,000
feet of poor ground.

SUMMARY OF LINE C

6,000 feet — Yonkers gneiss — good quality.
17,400 feet — Fordham gneiss — good quality.

6,800 feet — Along contact between limestone and gneiss

(questionable).
12,4-00 feet — Inwood limestone — with several bad zones.

6,400 feet — Manhattan schist — probably good quality.

3,000 feet — Fordham gneiss — probably good quality.

1,000 feet — Fordham gneiss — unknown quality.

9,800 feet — Ravenswood grano-diorite — mostly very good

rock.
18,400 feet — Almost wholly unknown.
81,200 feet— Total.

135

TABULATED SUMMARY— TYPES OP ROCK FORMATIONS

Line A (West) Line B (Central) Line C (East)

Per Per Per

Feet cent. Feet cent. Feet cent.

Yonkers gneiss 6,200 7.2 8,000 9.4 6,000 7.3

Fordham gneiss ■ 7.000 8.1 13,000 15.3 21,400 26.3

Contact zones 4,400 5.1 6,800 8.3

Inwood limestones 12,000 13.9 21,400 25.3 12,400 15.2

Manhattan schist 50,200 58.5 36,200 42.6 6,400 7.8

Ravenswood grano-diorite 9,800 12.0

Unknown 6,000 7.0 6,000 7.0 18,400 22.0

Total length 85,800 84,600 81,800

SUMMARY OF QUALITY

Line A

Per

Feet cent.

Good rock, 1st grade 42,400 49.4

Probably fair, 2nd grade 30,800 35.9

Probably poor, 3rd grade 6,600 7.7

Almost unknown 6,000 7.0

Totals 85,800 100.0

Line B

Per
Feet cent.

33,800 40.0

34,800 41.1

10,000 11.8

6,000 7.1

Line C

Per
Feet cent .

39,800

13,600

9,400

18,400

49.0
16.7
11.6
22.7

84,600 100.0 81,200 100.0

ARGUMENT ON CHOICE OF LINE

In judging the quality of rock and its suitability for this
conduit the factors of most weight are the same as those re-
peatedly mentioned in connection with other portions of the
Catskill Aqueduct line. That is, in brief, that the harder crys-
talline rocks of the Fordham gneiss and Manhattan schist
types wherever known to be free from fault crushing and surfi-
cial weathering are the best grade; that the more heavily
buried areas of these rocks, together with those limestone areas
that are known to be the most substantial of that class, should
be regarded as fair or second grade; that the more obscure
areas of limestone and all portions crossing faults or rivers
or crush zones in any rock must be regarded as poor or third
grade. This rating is based wholly on rock character and with-
out any consideration of cost of construction.

From the above it is clear that Line A has more " first
grade " rock than either B or C and less " third grade " ground.

Line C has three times as much " unknown " ground as
either B or C and less " first " and " second grade " rock.

136
In other words, the three lines are estimated

Line A
Per Cent.

Line B

Line C

Per Cent.

Per Cent

40.0

49.0

41.1

16.7

81.1

65.7

11.8

11.6

7.1

22.7

First grade rock 49.4

Second grade rock 35.9

First and second grades together 85.3

Third grade rock 7.7

Unknown ground 7.0

In addition to these differences of quafity, it appears from
a study of the areal geology along the respective lines that a
tunnel would pass across limestone contacts from one forma-
tion to another six times on Line A, four times on Line B, and
seven times on Line C. These may all be considered points
of probable weakness.

All of the lines cross belts of well-known weakness believed
to represent fault zones. Line A crosses three such zones,
Line B crosses two, and Line C crosses at least three.

Furthermore, all of the lines cut limestone for greater dis-
tances than seems desirable or necessary. The weakest ground
and the most uncertain quality of ground that can be mapped
falls within the limestone areas. In this respect Line A with
13.9 per cent, of limestone ground is preferable to Line B, with
25.3 per cent., or Line C, with 15.2 per cent.

From the above it is apparent that Line C is least defens-
ible. Line A has some advantage over both of the others,
especially in quantity of first grade rock, together with low
amount of the known poorest grade and small extent of the so-
called " unknown " ground.

The chief advantage of Line A over Line B lies in its
much smaller limestone area (12,000 feet vs. 21,400 feet or
13.9 per cent. vs. 25.3 per cent.), and the chief advantage of
Line A over Line C lies in its much smaller amount of " un-
known " ground (6,000 feet vs. 18,400 feet or 7.0 per cent. vs.
22.6 per cent.). On these grounds Line A is the least objec-
tionable of the three lines proposed.

But it is also clear from an examination of the field, as is
shown on the accompanying map (Sheet 16), that it is pos-
sible to avoid some known objectionable features or certain
parts of them and materially improve the figures by shifting
the line to a sort of compromise position between Line A and

137

Line B. This compromise line, or the trial lines from which
the final tunnel line may result, should follow as closely as pos-
sible the gneiss and schist ridges and should avoid the lime-
stone areas and known weak zones wherever possible.

DEPTH OF TUNNEL

The rock formations in general at the required depths are
no more objectionable on Manhattan island or in The Bronx
than at other localities on the Southern aqueduct. There are
weak places and crush zones to be crossed and some of them
cannot be avoided by any possible manipulation of the line,
but these most questionable spots constitute only a small por-
tion of the whole distance. The depth most suitable must de-
pend chiefly upon the depth necessary at the worst spots.

EFFECT ON CONSTRUCTION IF LINES ARE

SHIFTED

The question is best answered by reference to the geologi-
cal map. It will be noted especially that the belts of the dif-
ferent rock formations are usually narrow, and that they run
nearly parallel to the average direction of the lines. There-
fore a shift of line to no great distance would at many points
place it within an entirely different formation. It is also
notable that all of the lines run along or near the contacts be-
tween formations for long distances. At such points a very
small shift would wholly change the type of rock and rock
quality. Some shifting is desirable.

In general it may be assumed that the limestone belts
would be easiest and cheapest to penetrate whenever they are
fairly substantial, but they undoubtedly also contain the greater
proportion of weak and troublesome ground and must be con-
sidered least desirable from the standpoint of maintenance and
durability. The gneisses are probably most expensive to pene-
trate and the schists, medium. Both are more expensive than
limestone but both are more likely to prove acceptable for
other reasons.

The question of shifting the lines is a complicated one and
hinges more upon rock condition, durability, and location of
weak zones than on any possible cost.

138

ADVISABLE CHANGES IN LINES

None of the suggested lines are defensible from a geologic
point of view for the reason that a much better one may be ob-
tained by no very serious shifting.

In the general consideration of relative advantages of dif-
ferent possible locations of the line, it is believed that the fol-
lowing large features are of most immediate importance :

( 1 ) The ridges as opposed to the valleys.

(2) The hard formations as opposed to the softer ones.

(3) The crossing of few contacts as opposed to crossing
many.

(4) The location well within a formation as opposed to lo-
cation along a contact.

It is distinctly preferable from a geologic standpoint (1)
to follow the ridges, (2) to keep in the hard formations, (3)
to avoid many changes from one formation to another, (4) to
keep away from contact lines, and (5) to avoid weak zones,
if possible, or cross known troublesome zones at the most ad-
vantageous point.

RECOMMENDATIONS OF NEW LINES F, G, H, I

The original lines A, B and C are marked on the map in
blue (Sheet 18). In addition several trial lines are sketched
in yellow, any one of which would give better geological con-
ditions than any of the three original lines. The newly sug-
gested trial lines differ from each other chiefly in the points
at which they cross the limestone belts and weak zones. In
all of them the central idea has been to follow the gneiss and
solid ridges as persistently as possible. All unite at Centra!
park and are intended to follow Fifth avenue, Broadway, the
Bowery and Market street to East river along one of the origi-
nal lines. North of Central park they differ from the original
lines. The westerly one crosses the Harlem river at 176th
street and may be designated Line F. The easterly line may
also cross the Harlem river at 176th street and may be desig-
nated Line G; or it may continue southward and cross the
Harlem at 155th street. It will then join the first one in the
vicinity of 144th street and is called Line H. The alternative
easterly one which crosses the Harlem at 155th street and fol-
lows Seventh avenue to Central park is Line I.

139

Details of rock conditions along these lines are as follows :
Line F — (Westerly) Beginning at Hill View Reservoir

7,600 feet — Yonkers gneiss — good quality.
15,000 feet — Fordham gneiss — good quality.
2,000 feet — Fordham gneiss — probably second grade.
1.200 feet — Flarlem River crossing — partly limestone — third

grade.
14,800 feet — Manhattan schist — good quality.
1,600 feet — Manhattanville crossing — third grade — some

limestone.
2.600 feet — Manhattan schist — good rock — through Morning-
side park.
800 feet — At south end of Morningside park — perhaps some

limestone — second grade.
1,400 feet — Manhattan schist — good — to junction.
12,000 feet — Manhattan schist — along Central park — good.
20.600 feet — To East river — Manhattan schist — less known —

(fair) (second grade).
6,000 feet— To Brooklyn—" unknown."
85,600 feet— total.

Line G

8,400 feet — Yonkers gneiss — good rock.
17,600 feet — Fordham gneiss — good rock,

which brings it to the Harlem river where the other line (F)
is joined. Although the line is about 1,400 feet longer, it
avoids some low ground (200 feet) along the east bank of the
Harlem river, some of which may be in poor condition. Total
length of line, 87,000 feet.

Line H

8,400 feet — Yonkers gneiss — good quality.
23,800 feet — Fordham gneiss — good quality — to Harlem river.
1,000 feet — Crossing Harlem river — probably fault zone in

gneiss.
800 feet — Fordham gneiss — good quality.

140

1,000 feet — Limestone — second grade.

1,200 feet — Manhattan schist — good quality — to junction

with the first line (F) at 145th street.

From this point the line is the same as F and G. Its chief
advantage is the great distance which it has in Fordham gneiss.
Total length of line, 85,600 feet.

Line I

8,400 feet — Yonkers gneiss — good quality.
23,800 feet — Fordham gneiss — good quality — to Harlem river.
1,000 feet — Crossing Harlem river — probably fault zone in

gneiss.
4,400 feet — Fordham gneiss — good rock — to 135th street.
4,600 feet — Inwood limestone — probably fair — second grade.
2,000 feet — Inwood limestone — probably poor quality — third

grade.
1,000 feet — Manhattan schist — good quality.

At this point the line unites with Line F. Total length of
line, 83,800 feet.

A tabulation of these figures indicating estimated extent of
rock types is given below :

Line P Line G Line H Line I

Feet Feet Feet Feet

Total length of line 85,600 87,000 . 85,600 83,800

Length in Yonkers gneiss 7,600 8,400 8,400 8.400

Length in Fordham gneiss 17,000 17,600 25,600 29,200

Length in Inwood limestone and mar-
ginal contacts 3,600 3,600 3,400 6,600

Length in Manhattan schist 51,400 51,400 42,200 33,600

COMPARATIVE SUMMARY OF TYPES OF FORMATION (COMPARATIVE
DISTANCES ARE EXPRESSED IN PERCENTAGES)

A B C F G H I

Yonkers gneiss 7.2 9.4 7.3 8.8 9.6 9.8 10.0

Fordham gneiss 8.1 15.3 26.3 19.8 20.2 29.9 34.8

Contact zones 5.1 .... 8.3 \ A 9 ± 1 « Q 7 fi

Inwood limestone 13.9 25.3 15.2/ *^ 41 6A) 7 ' 8

Manhattan schist 58.5 42.6 7.8 60.0 59.0 49.3 40.1

Ravenswood grano-diorite 12.0 .... .... ....

♦Too little known to classify 7.0 7.0 22.6 7.0 6.9 7.0 7.1

*Now known to be chiefly grano-diorite.

As a group it is especially noticeable that the new lines
F, G, H, I, have a very much lower percentage of contact

141

beds and limestone. The percentages of gneisses have been
notably increased, and the unknown and questionable forma-
tions have been reduced to approximately the lowest terms.

ESTIMATED SUMMARY OP QUALITY

Line F
Feet

Good rock, first grade 53,400

Fair rock, second Rrade 23,400

Poor rock, third grade 2,800

Unknown (Brooklyn) 6.000

Totals 85,600

Line G
Feet

Line H
Feet

Line I
Feet

56,800

21,400

2,800

6.000

87,000

54,600

22.400

2,600

6,000

85,600

49,600

25.200

3,000

6,000

88,800

In other words, these new lines show :

Line F
Per cent.

Line G
Per cent.

Line H
Per cent.

Line!
Per cent.

First grade rock 62.3

Second grade rock 27.3

First and second grades together 89.6

Third grade rock 3.2

"Unknown" ground 7.0

65.3

24.6

89.9

3.0

6.9

63.8

26.1

89.9

3.0

7.0

59.1

30.0

89.1

3.6

7.1

A comparison on this basis with the original lines A, B,
C indicates that these new lines F, G, H, I, make a better show-
ing, especially on first grade rock and that all show decided
reduction on the third grade ground.

A b c F G H I

First grade rock 49.4 40.0 49.0 62.3 65.3 63.8 59.1

Second grade rock 35.9 41.1 16.7 27.3 24.6 26.1 30.0

First and second 85.3 81.0 65.7 89.6 89.9 89.9 89.1

Third grade rock 7.7 11.8 11.6 3.2 3.0 3.0 3.6

♦Unknown 7.0 7.1 22.7 7.0 6.9 7.0 7.1

*Xow known from explorations to be first grade.

On geological grounds, therefore, it is confidently believed
that any one of the new lines (F, G, H, I) would give de-
cidedly better results than any one of the original ones
(A, B, C). The poor and the questionable and the unknown
ground can not be wholly avoided by any possible line, no
matter how roundabout. In these lines, approximately as
drawn, the objectionable points are reduced to a minimum
with almost no increase in total length of conduit. The ob-
jectionable portions are also restricted in large part to the
Harlem river, where we already have the experience of the
last aqueduct (the Xew r Croton aqueduct) as a guide, and a
very few other spots.

142

General Conclusions

Line I is the shortest possible defensible line. Its chief
objectionable feature is a rather long stretch, 6,600 feet of
limestone, from 135th street to Central park, upon the quality
of which there are no data. It crosses the Harlem River fault
probably in gneiss. But it crosses the extension of the Man-
hattanville fault in limestone.

Lines F, G, and H are almost equally defensible. Line G
is longest, but is in some respects — especially in following the
ridge crests — one of the best possible locations.

It should be appreciated that many other matters, such as
municipal works already completed or projected, or matters
of engineering practice, are likely to make it necessary to
modify any line proposed, and that the final line is more likely
to be a compromise, considering all interests.

A graphic representation of the comparative merits of the
proposed lines is given in Sheet 5. This is strictly a geologic
study. The lines are properly placed on an outline map of the
City, corresponding exactly to those drawn on the geologic
map, Sheet 18. The geologic formations that each would cut
are represented on longitudinal sections which follow each line,
and the attitude and structure of each formation are indicated.

REVISED LINES

Subsequently two revised lines based upon the preceding
studies were examined to determine preference. Later one
of these, or a slight modification of it, was adopted as the one
to be explored. It was soon determined on the same reason-
ing as was applied to the first group of lines that the most
westerly line — the line keeping as much as possible within
the gneiss and schist ridges — would be the most likely to give
satisfactory conditions. By this method of selection the un-
known or untested and doubtful ground was reduced to its
lowest limits. It was found that nearly all of the very weak
spots could be located by inspection on the northern portion
of the line, but south of 59th street the question is decidedly
more difficult because of the heavy drift cover. No rock out-
crops occur south of 30th street, and one is reduced to the evi-
dence of deep borings.

• »*L* «**».

*b •*» h ■**-»

-4

143

Points for Exploration North of 59th Street

It was soon evident that extensive exploratory work would
have to be undertaken for additional data and the following
points were selected at which to begin :

(1) The Harlem River crossing, where the distribution
conduit line crosses the river just below High bridge (see
later description). The only good evidence as to character of
rock at this place is from the pressure tunnel of the New
Croton aqueduct which crosses the river a short distance above.

(2) The Manhattanville cross valley (125th Street de-
pression). This is the most important cross depression on the
Island of Manhattan. It is apparent after a little investigation
that the bed-rock floor lies deep, and that if it were not for
the drift-filling, the tides would surge through this valley
making a direct connection between the Hudson and the East
river. It was the least known as to depth and character of
any point along the proposed line.

(3) The depression between Morningside and Central
park. At that place limestone on the crest of a pitching anti-
cline reaches farther south than on either side and is more
deeply eroded. The other zones of large importance are in
southern Manhattan, the geology of which was made a special
study.

Special Study of the Geologic Conditions South of 59th

Street

Below Central park there is now little to be- gathered from
a study of the present surface. But as far south as 31st street
the bed-rock geology is pretty well known from earlier reports
and from recent improvements that have exposed the under-
lying rock. All of this portion is mapped as Manhattan schist
except one small area of serpentine at 59th street between 10th
and 11th avenues. There is no reason to modify this usage. A
careful study of a great number of rock borings from the
Pennsylvania Railroad tunnel across Manhattan at 32nd street
proves beyond question that bed-rock is Manhattan schist, in-
cluding almost all known variations and accompaniments, for
the whole width of the island along that line.

Still farther southward the points that have yielded exact
information about bed-rock are less numerous, and below 14th

144

street are confined to deep borings or an occasional very deep
excavation for foundations. Even these sources of informa-
tion are lacking over large areas. The greater number of bor-
ings available are along the water front. Their distribution
is such as to indicate that the west side and central portion and
southerly extremity of the island are all underlain by Man-
hattan schist. This is true eastward to the East river at 27th
street, and as far eastward as Tompkins square at 10th street
and almost to the Manhattan tower of Brooklyn bridge in that
vicinity.

To the eastward of these limits, i. e., to the eastward of the
line projected from Blackwell's island to the Manhattan tower
of Brooklyn bridge, there is a more complicated geology. The
borings of the East River water front are decidedly variable.
They are certainly not all Manhattan schist of the usual types.
Those most unlike the Manhattan are at the same time most
like some varieties of the Fordham, and indicate that these
formations both occur. The lack of any data in the beginning
of this investigation except on the water front made it impos-
sible to # draw more than very general lines. Drawn in this
way, the lines of course are too straight, but it is certain that
they indicate more nearly the actual existing areal distribution
of formations than any of the maps now in existence. They
indicate a southward extension of the Blackwell's Island belt
of Fordham gneiss toward the Manhattan tower of Brooklyn
bridge. How much of this anticlinal fold of Fordham actually
brings this formation to the surface it is impossible to say, but
that it may be expected to be encountered along this line is evi-
dent.

On the east side a parallel belt of limestone is indicated and
this again is succeeded by a Fordham gneiss area which occu-
pies the rest of the eastern margin. Explorations made along
the line of the gas tunnel across East river at 72nd street indi-
cate comparatively narrow belts of limestone there in both
the east and west channels. The limited width of limestone
at these points, together with the occurrence of two strongly
developed disintegration zones, seem to indicate rather exten-
sive squeezing out and faulting of this formation along fault
planes parallel to the strike. Such movements are capable of
cutting out the intermediate limestone entirely from between

145

the schist and gneiss. It is impossible to say, in the almost
total lack of data bearing upon the question, how much of such
modification exists. The" intermediate belt is indicated on the
accompanying map (Sheet 6), as a limestone area. At one
point at least the limestone does occur in the older borings,
i. e., on the southeastern margin of the Manhattan pier of the
Manhattan bridge (Bridge No. 3), at the foot of Pike street.

On the Brooklyn side no formations of this series except
the Fordham and its associated igneous masses, such as the
Ravenswood grano-diorite, have been identified within the area
under study. Limestone is reported (Hobbs reference to
Veatch) near Newtown creek, a little beyond the eastern
margin of the present map.

The East River Area
manhattan side

In all of the area south of 59th street, structural features
are even more obscure than the areal geology.

There is no reasonable doubt but that weak zones will be
found as frequently in the Manhattan schist portion of this
area as on the line north of 59th street, but they can not be in-
dicated as closely. No cross fault of large consequence can
be identified, but there is some evidence of a minor zone that
should be encountered on Fifth avenue, in the vicinity of 32nd
street. The Pennsylvania tunnels and the subway both cross
this line and so far as known there were no serious weaknesses
developed. There is nowhere any evidence of an important
depression like the Manhattanville valley.

It is confidently believed that the problems on this southerly
portion of Manhattan are involved chiefly with the longitudinal
structures produced by folding and faulting and subsequent
disintegration along such zones.

Two trial lines, marked P and Q, were laid out across the
East river (see location on map, Sheet 18). From 59th street
to the East river there seems to be no reason for a preference
between the two lines P and Q. On the Brooklyn side likewise
there is no known geological reason for preference. Such basis
for choice as is now known relates to the East River channel
alone. Since this is regarded as a very difficult section of the

146

line to explore and probably the most uncertain section to esti-
mate as to condition and consequent depth of tunnel, it would
be especially useful to be able to make a decisive selection of
crossings at once.

Such evidence as has any bearing upon this question has
already been used in formulating the interpretation of geologic
structure given in the foregoing sections of this report. If
the succession and boundaries of formations as outlined are
reasonably close to the actual conditions, it would appear that
Line P (the southerly one just above Manhattan bridge) has
some advantage over Line Q (near Williamsburg bridge). The
chief elements in this advantage are as follows :

(1) It would appear that Line P might be wholly within
the Fordham gneiss in the East River section, while Line Q
may cross two contacts.

(2) From the evidence of borings made in the East river
at 14th street it appears probable that a belt of schist similar to
Manhattan schist in quality (whether accompanied by lime-
stone or not there is no direct evidence) lies in the river chan-
nel toward the east side and in all probability extends south-
ward in the middle of the river at Williamsburg bridge. This
would be cut bv Line Q. The uncertainties of this association
are of sufficient importance to throw the balance of present
choice toward Line P.

(3) If the theory that the East River course is due chiefly
to zones of weakness following fractures or faults is true, their
possible comparative condition as they cut through different
formations must be taken into account. There is little doubt
on this point but that, in zones of similar original disturbance,
those in the Fordham gneiss have suffered less extensively from
disintegration than those cutting either the limestone or schist.
Therefore, obscure as it may be, the preference is again in
favor of Line P.

(4) If, as now appears, the present East river is displaced
from its old channel by glacial drift, so that it is essentially an
evicted stream, there may not be as pronounced a channel or
as weak ground to cross at such point as at those where the old
channel is still occupied. In such cases both of these lines are
favorable.

(5) On the other hand, the crossing of Line P is almost a

147

mile nearer to the great Hudson gorge, to which doubtless this
portion of the preglacial East river was tributary, and conse-
quently its bed-rock channel, if it is the real preglacial channel,
may be expected to be deeper and the accompanying disin-
tegration (so far as it may be controlled by this factor) may
be expected to reach lower than at points in similar surround-
ings farther up stream. It is impossible to say how much
weight should be given to this objection. It does not seem to
be of sufficient importance to fully offset the favorable features
indicated in Items 1, 2 and 3.

On the basis of these studies Line P (the southerly one)
near Manhattan bridge was chosen as the site of preliminary
exploration promising the most favorable results. Later this
was shifted a short distance without introducing any new con-
ditions.

The accompanying map, Sheet 6, summarizes the results of
this study of southern Manhattan. The formations and general
arrangement of them is the same as on the original drawn be-
fore additional explorations were made, but the boundaries are
corrected so as to be in keeping with the latest exploratory
investigations.

SPECIAL EXPLORATION ZONES

Explorations by borings and other methods have been made
at all questionable or uncertain points along the line. As was
expected in the beginning five places have required elaborate
exploration and some exceptional conditions have been proven.
The original geological investigation based upon surface study
as outlined in the foregoing pages served to locate these spots
accurately.

These places or zones, now sufficiently well known to per-
mit accurate statement of geologic conditions, are as follows :

(1) The Harlem River crossing at 167th street, where the
aqueduct will cross from a ridge of Fordham gneiss beneath
the Harlem river and where the whole thickness of Inwood
limestone will be cut, reaching the ridge of Manhattan schist
above the Speedway on Manhattan island.

(2) The Manhattanville cross valley, a low pass crossing
the island at about 125th street (Manhattan street). The part
explored extends from St. Nicholas to Morningside parks and
crosses a zone with very low rock floor in the Manhattan schist.

148

(3) From Morningside to Central parks. The line crosses
the strike of the formations at this point and cuts a longitudinal
fault and anticlinal fold which tends to bring the Inwood
limestone within surface influence.

(4) The Lower East Side zone. On Delancey street east
of the Bowery, the line crosses the rock structure and at this
point the whole series of crystalline formations appear. Be-
sides complicated structure there is also exceptionally deep
alteration or decay of bed-rock.

(5) The East River crossing — from the foot of Clinton
street to Bridge street, Brooklyn.

Harlem River Crossing

Geologically the Harlem river between 155th and 200th
streets has the same relation to local formations for the whole
distance. It flows on the Inwood limestone bed which stands
almost exactly on edge, while the east river-bluff is formed by
the underlying Fordham gneiss, and the west, by a strong
escarpment of Manhattan schist which extends southward
throughout the whole of Manhattan forming the backbone of
the island.

At the selected crossing a short distance below High bridge,
near 167th street, the schist-limestone contact is in the river
and appears to be a low weak spot (see detail of record). The
limestone-gneiss contact, however, is in the flat east of the
river bank, near Sedgwick avenue and seems to be more sub-
stantial. The structural detail and relations are shown on the
accompanying profile and cross-section (Sheet 8).

It is observed by examination of the data secured by bor-
ings that the limestone formation at this point is exceptionally
heavily impregnated with pegmatite dikes and stringers, and
that interbedded schist layers are large and numerous.

The weakest spot found lies at the contact between schist
and limestone where there is probably some longitudinal dis-
placement.

A similar condition was found at the New Croton crossing
2,000 feet farther north. On the whole bad decay does not
extend very deep — 150 to 200 feet.

Several borings have been made and on them is based the
only judgment possible of the actual structure and physical

the river on High bridge.

150

condition of rock. In most cases the evidence is easily inter-
preted for these points. The most weakened spot, as well as
the most difficult to interpret in all its detail, is the limestone-
schist contact. It is judged that Hole 17 cut through this con-
tact zone. This boring is located in the river 50 feet from the
Speedway (west bank) on the proposed tunnel line which
crosses a short distance south of High bridge. It is known as
Hole 17/C38. Because of the somewhat unusual quality of
material at this place, as indicated by the wash and core saved,
and because of the suggestion it gives about the structure and
condition of rock beneath the river, the record and interpreta-
tion notes are given.

feet to 13 feet — Water.

13 feet to 46 feet — Black river mud (mostly silt).

46 feet to 48 feet — Sand with decayed wood (peaty wood).

48 feet to 70 feet — Quartz and garnet sand rather clean

(glacial).

46 feet to 70 feet — Lumps of peaty matter coming to the sur-
face at intervals indicating occa-
sional small layers of peat (glacial).

70 feet to 78 feet — Mixed sand (glacial).

92 feet — A core of Triassic contact shale (a drift boulder

from the Palisade margin). At this
point also a piece of Manhattan
schist (boulder).

95 feet — Four pieces of diabase (Palisade trap) from another

drift boulder.

96.5 feet — Five pieces of Inwood limestone (boulder) fol-
lowed by a piece of quartzite and
several mixed pebbles indicating
glacial drift origin.

114 feet to 119 feet — A buff yellow sand with much pearly

mica flakes. Effervesces with acid.
This shows no foreign matter. It is
chiefly residuary decayed rock in
place and represents siliceous and
micaceous limestone. It is decaved,
very impure, Inwood limestone.

119 feet — Clay with pieces of flinty quartzite, probably from a

small quartzose seam in the lime-
stone.

151

120 feet to 126 feet — Light flaky yellow material. Much

pearly mica with earthy matter.
Effervesces in acid. Residuary
from Inwood limestone.

128 feet — White and drab lumpy residuary matter (kaolin)

and earthy substances. Effervesces.
A more impure Inwood. Also shows
several pieces of core of a porous,
rotten limestone. Inwood.

129 feet to 134 feet — Reddish-brown lumps. Effervesces a

very little. Mostly clay but still no
foreign matter. Residuary material
from a more siliceous bed. A few
pieces of hard, impure limestone at
133 feet.

134 feet — Pieces of a porous quartz chlorite rock with little

lime. Is a leached quartzose rock
evidently a sandstone layer in the
limestone. Rock belongs to the In-
wood formation.

135 feet to 143 feet — Dark micaceous matter containing

chiefly biotite, a pearly mica, and
quartz. Rock is a decayed schist
bed — the transition between Inwood
limestone and Manhattan schist.

143 feet to 151 feet — Dark brown micaceous material. Biotite

and quartz — chiefly. Rock is de-
cayed schist (transition rock). At
146 feet encountered pieces of a
pegmatite veinlet. All pieces except
one are pegmatitic — the other one is
calcareous sandstone, fallen into this
lot from the 134- foot level.

151 feet to 160 feet — Chunks of pegmatite (a vein rock).

151 feet to 161 feet — The mica washings continue the same

as at 143 feet to 151 feet. Rock is
a transition schist with pegmatite
stringers.

164 feet to 169 feet — Brownish yellow micaceous matter

(loose). Mica, quartz, chlorite,
lime. Effervesces.

152

164 feet to 173 feet — Many pieces of typical Manhattan

schist. A fair amount of core for
the conditions. Rock is not so badly
decayed but is broken into small
pieces. Rock is Manhattan schist of
typical character.

SUMMARY

( 1 ) The material is chiefly river silt down to 46 feet.

(2) Lighter glacial deposits 46 feet to 78 feet.

(3) Heavy bouldery drift 78 feet to 97 feet.

(4) Uncertain (insufficient data) 97 feet to 114 feet.

(5) Residuary micaceous decay products from Inwood
limestone 114 feet to 135 feet.

(6) Decayed transition schist bed with some lime, but
chiefly like the Manhattan schist 135 feet to 161 feet.

(7) More calcareous schist 161 feet to 164 feet.

(8) Typical Manhattan schist 164 feet to 173 feet.

INTERPRETATION

(1) Foreign matters, glacial and recent deposits, continue
to a depth of between 97 and 114 feet.

(2) Rotten formations (residuary matter) in place begin
at least as high as 114 feet. There is no foreign material
below that point except grains that have fallen into the hole
from above.

(3) More solid rock begins at 164 feet.

(4) The upper portion of the rotten rock (114 feet to 135
feet) is calcareous enough to belong to the Inwood limestone
formation. The lower 9 feet (164 feet to 173 feet) is typical
Manhattan schist. The intermediate ground 135 feet to 164
feet is transition variety.

(5) The drill has cut the contact between Inwood and
Manhattan formation.

(6) If this identification of the badly decayed matter is
correct, the contact at this point dips steeply eastward, i. e.,
it is overturned.

(7) Both types of rock are shown to be extensively
decayed.

153

(8) The worst (deepest) decay zone probably lies a little
farther east, and follows the dip of the micaceous limestone
near the contact.

These conditions are indicated on the accompanying cross-
section (see Sheet 8).

The conditions indicated bv this one hole are consistent
with those known for the New Croton Aqueduct tunnel 2,000
feet farther north where, according to the engineers' drawings,
the formations also are overturned. Fifty feet of decayed rock
is shown in this hole. The contact is undoubtedly decayed
considerably to a depth of more than 200 feet below water-
level.

Another boring put down to test conditions at still greater
depth nearby explored the rock to -442.7 feet. Because of
the information it gives about the deeper bed-rock, a summary
of the record based upon examination of the material is given :

HOLE 42 (75 FEET FROM SPEEDWAY, 25 FEET EAST OF HOLE 17)

feet to -94.1 feet — River muds and various types of drift

similar to Hole 17.

-94 feet to -96 feet — Iron cemented sand — both drift sand

and local angular material.

-98 feet to -127 feet — Micaceous clay — residuary decayed

matter — with choppings of
calcite, quartz, mica and
chlorite representing weath-
ered Inwood limestone.

-127 feet to -135 feet — Core — Inwood limestone (impure).

-135 feet to -149.5 feet— Pegmatite.

-149.5 feet to -197 feet — Inwood limestone — .typical — stand-
ing almost vertical in upper
portion but changing to about
45 degrees and farther down
to 60 degrees. Good sound
rock.

-197 feet to -241 feet — Manhattan schist — of typical sort —

and in sound condition, but
becoming somewhat more
broken and altered near the
bottom. Dip about 60 de-

155

grees to 80 degrees and even

more. Average probably 75
degrees to 80 degrees.

-241 feet to -295 feet — Manhattan schist — typical — dip vari-
able but mostly above 70 de-
grees to vertical — some peg-
matite — fractures are at high
angle. Rock sound.

-295 feet to -302.5 feet — Pegmatite.

-302.5 feet to -442.7 feet — In wood limestone — typical — good

quality — dip 70 degrees to
very flat — one piece not over
35 degrees but mostly ob-
scure.

An interpretation summary is as follows :

feet to -94 feet — River muds and drift rilling (glacial and

recent).
-94 feet to -96 feet — Transition to residuary matter.
-96 feet to -127 feet — Residuary matter and badly decayed

Inwood limestone.
-127 feet to -197 feet — Inwood limestone.
-197 feet to -302 feet— Manhattan schist.
-302 feet to -442.7 feet — Inwood limestone.

GEOLOGIC CROSS-SECTION

The accompanying cross-section (Sheet 8) embodies an
interpretation of all the data secured in the Harlem river. It
is now known that the limestone is overturned slightly at both
contacts. The nature of these contacts makes it seem probable
that there is very little of the limestone squeezed or cut out by
movement. Therefore this crossing gives a fairly accurate
measure of the thickness of the Inwood. This is approximately
750 feet. No section about New York City is more accurately
determined.

Manhattanville Cross Valley

In northern Manhattan the schist ridge which forms the
backbone of the island and has a relief of more than 100 feet,
is cut across by a prominent valley that extends from the Hud-
son at 130th street eastward to the Harlem flats and East river

156

This vallev is nowhere more than 25 or 30 feet above the sea-
level and is drift rilled. Previous to the recent boring explora-
tions of the Board of Water Supply its true depth to rock floor
was unknown. The few borings recorded, however, indicated a
depth of more than a hundred feet. One such boring at 129th
street and Amsterdam avenue is reported as penetrating 109
feet from surface without touching rock. Another of similar
results is located at 125th and Manhattan streets where a depth
of 204 feet failed to touch rock.

Besides determining rock floor in the present case, it is im-
portant to determine rock structure and conditions. It ap-
pears from surface features that this cross valley probably fol-
lows a fault zone along which there has been weakening of the
rock and consequent disintegration and decay. If this is so it
would be advantageous to find the limits of it and determine
what displacement effects were produced. It has been sur-
mised by all students of local geology that such cross faults
may lift the blocks on the south side of them, one of the chief
indications being the fact that in spite of a strong southerly
pitch in all the formations they do not rapidly disappear below
sea-level.

The accompanying profile and explanatory section indicates
the principal results of exploration (see Sheet 9). Badly
crushed ground has been found in the holes near the north end
of Morningside park but the rock, when found, is not very badly
decayed. The rock floor is very low, almost 200 feet below
sea-level at the lowest. It appears that if the drift were
stripped off from this valley the Hudson and Long Island
sound would unite across the Harlem flats and Manhattanville
forming a channel and outlet much deeper than the present
East River course.

The glacial drift of this valley is prevailingly fine modified
drift some of which is probably stratified and fairly well as-
sorted. This is more strikingly true of the southerly exten-
sion of this low ground southward along Morningside park.
A very deep and prominent preglacial gulch came down from
the gap between Morningside and Central parks.

It is not yet proven that the fault has really raised the
Morningside block. At least if there is such displacement it
is not of sufficient amount to bring up a different formation at

157

any point yet examined. It would be possible for the limestone
to be brought up to the surface, but except for a few pieces of
interbedded limestone no evidence has been secured. The oc-
currence of this, however, is thought to indicate proximity to
the limestone contact.

GENERAL GEOLOGIC CONDITIONS ESTABLISHED

Fourteen borings have been made for the special purpose
of determining exact conditions. On the data of these holes
there are several features now established beyond question that
were originally given only as probabilities. The most important
of these may be enumerated as follows :

(1) A very deep cross valley is now proven between 123rd
and 126th streets crossing Morningside Avenue East, and its
profile can be plotted.

(2) A part of this ground is badly broken, as if belonging
to a fault zone, but most of the floor thus far tested is not in bad
condition, i. e., it is not very badly crushed or decayed.

(3) The drift cover in this cross valley is more than 200 feet
deep over a distance of more than two blocks on the proposed
line (from 123rd street to Manhattan street).

(4) The limestone contact lies more than 300 feet east of
the proposed tunnel line at this Manhattan cross valley.

(5) At 121st street the limestone-schist contact stands very
steep and is probably slightly overturned, so as to dip steeply
to the east. This is indicated by the data of Hole 33, which
lies to the east side of the line.

(6) The contact line approaches nearer to Morningside
park in passing southward, touching the park between 1 10th and
113th streets, but the contact is probably not overturned in
this southerly extension.

Morningside to Central Park

The contact between Inwood limestone and Manhattan
schist follows nearly parallel with the Morningside Park boun-
dary on the east side, but, because of its form, actually touches
the park only at the south end between 110th and 113th streets.
At the north end it lies off more than half a block to the east.
The Manhattan schist forms an escarpment because of its more,
resistant character and this eastward facing cliff and slope

I

I

159

forms Morningside park. St. Nicholas park, farther north,
from 128th to 141st streets, has the same structural relations,
and the same conditions prevail still further northward. In
both cases the present escarpment stands back from 200 to
500 feet from the actual contact, and is covered heavily with
drift.

As the formations all pitch southward and are closely
folded, the higher formations gradually appear and at 110th
street another parallel ridge of schist comes in above the
limestone in the trough of the next syncline to the east. This
forms the north end of Central park and from this point south-
ward Manhattan schist is continuous. But betw r een the Morn-
ingside belt of schist and the Central Park belt at 110th street
lies an anticline of Inwood limestone also pitching southward,
gradually passing beneath the schist, which encroaches upon it
on both sides. A few blocks farther south it passes wholly
beneath the schist, which from that point is continuous as the
rock floor formation.

This anticlinal wedge together with its accompanying
structures and rock condition was the subject of some detailed
exploration.

The records of a few drill holes together with an interpre-
tation of the data will serve the present purpose of illustrating
the geologic features of this section.

HOLE 7, ON 113TH STREET, CORNER OF MANHATTAN AVENUE

Surface elevation, 38 feet.

Rock floor at depth of approximately 165 feet — Elevation
-127 feet.

Material

feet to 85 feet — to Elevation -47 feet — modified drift.

85 feet to 165 feet — to Elevation -127 feet — sand with much

more clay, part of which may be de-
cayed rock.

165 feet to 240 feet — to Elevation -202 feet — disintegrated

rock ledge. Some micaceous type
believed to be the transitional
facies of the schist-limestone con-
tact.

160

242 feet to 280.71 feet— to Elevation -242.71 feet— Inwood,

very coarse type, of limestone. Poor
core showing. Much broken.

HOLE 16, CORNER OF MANHATTAN AVENUE AND HOtH STREET

Surface elevation, 55 feet.

Rock floor at depth of 159 feet — Elevation -104 feet.

Material

feet to 44 feet — to Elevation 11 feet — filled ground and

mixed material.

44 feet to 159 feet — to Elevation -104 feet — fine sands and

silts interpreted as chiefly modified
drift. Much of it very fine and the
lower portion rather micaceous and
angular throwing a little doubt on
the exact line of demarcation be-
tween drift and residuary matter.

159 feet to 161 feet — to Elevation -106 feet — core of Man-
hattan schist.

171 feet to 186 feet — to Elevation -131 feet — decayed rock

in place, some micaceous type,
coming out as mud.

186 feet to 228 feet — to Elevation -173 feet — micaceous red-
dish mud with variable amounts of
angular quartz grains. Certainly
residuary decayed rock.

228 feet to 270. feet — to Elevation -215 feet — similar resid-
uary matter less highly colored
passing from reds into grays and
coming out as soft material.

270 feet to 305 feet — to Elevation -250 feet — grayish mica-
ceous and quartzose residuary mat-
ters. With much silvery mica and
chloritic grains near the bottom.

305 feet to 335 feet — to Elevation -280 feet — Inwood lime-
stone, core, ordinary type. No
core recovered above this point
except for two feet between 159
feet and 161 feet.

161

HOLE 36 AT 108TH STREET AND MANHATTAN AVENUE

Elevation of surface, 63 feet.

Rock floor (decayed) at depth of 55 feet — Elevation 8
feet.

Depth to solid core — 248 feet — Elevation -185 feet.

Material

feet to 55 feet — Elevation 8 feet— modified drift (fine

silts).

55 feet to 155 feet — to -92 feet — micaceous soft material

with broken sand — decayed mica-
ceous rock.

155 feet to 215 feet — to -152 feet — reddish mud of similar

constituents. Is decayed rock col-
ored by iron.

215 feet to 240 feet — to -177 feet — transition to more gray-
ish and greenish soft matter.

240 feet to 245 feet — to -182 feet — greenish mica rock — a de-
cayed chlorite, mica quartz, schist
layer.

248.33 feet to 254.25 feet— from Elevation -185.35 to -191.25

feet — chloritic Inwood limestone.
A summary of these data gives :

feet to 55 feet — drift.

55 feet to 245 feet — decayed rock ledge.

248 feet to 254 feet — solid rock ledge (limestone).

HOLE 2 AT 123RD STREET, 100 FEET EAST OF MORNINGSIDE PARK

EAST

Surface elevation, 30 feet.

Rock floor at depth of 220 feet— Elevation -190 feet.

Material

feet to 13 feet — to Elevation 17 feet — soil and mixed drift.
13 feet to 220 feet— to Elevation -190 feet— modified drift

— mostly assorted sands and silts.
220 feet to 245 feet— to Elevation -215 feet— soft decayed

schist.

162

245 feet to 355 feet — to Elevation -325 feet — Manhattan

schist much broken — poor core re-
covery — worst material at about
225 feet to 240 feet and again near
bottom. Formation evidently much
shattered and considerably decayed.

HOLE 33 ON 12 1ST STREET, 300 FEET EAST OF MORNINGSIDE PARK

EAST

Surface elevation, 31 feet.

Rock floor at depth of 195 feet — Elevation -164 feet.

Material

feet to 25 feet — soil and mixed drift.

25 feet to 195 feet — to Elevation -164 feet — drift, mostly

modified drift — assorted sands and
fine silts.

190 feet to 195 feet — coarser material — pebbles. %

195 feet to 200 feet — to Elevation -169 feet — Inwood lime-
stone, coarse limestone of usual
type.

200 feet to 237 feet— to Elevation -206 feet — Manhattan

schist.
Ordinary type and in good condition (for interpretation see

later comments).

CONDITION OF THE LIMESTONE-SCHIST CONTACT ALONG THE

MORNINGSIDE SECTION

The finding of Inwood limestone above the Manhattan schist
in Hole 33 at 121st street east of Morningside and the fairly
sound condition of both types raises the general question of the
condition of contact zones as compared with fault zones.

There are three important facts to consider bearing on this
case:

(1) The contact zones are commonly weaker than either
formation alone.

(2) At this particular point an abnormal relationship is
shown by the overturned strata (the limestone lying above).

163

(3) The fault zones are always weak and extensively de-
cayed.

Because of the abnormal position of the limestone here,
lying as it does overturned, a weaker more pervious rock upon
a more substantial and less pervious one, it appears to be rea-
sonable enough to find the limestone and schist fairly well pre-
served, under conditions where a vertical or a normal position
would have encouraged decay because permitting a more ready
circulation.

But fault or crush zones are more extensively decayed than
the simple contact or transition zones. Therefore where an
especially extensive decay is encountered it probably is to be
associated with a crush zone due to fault movement rather
than with anv other structure.

A further inference seems allowable from the data of these
holes. It is probable that these fault zones do not follow the
contacts or bedding exactly but cut across at low angles, some-
times coinciding with the contact lines and sometimes falling
wholly within the limestone or the schist.

GREAT DEPTH OF DECAY AT SOUTH END OF MORNINGSIDE PARK

The finding of approximately 150 feet of decayed rock in
Hole 16 and of nearly 200 feet of similar type in Hole 36, all
so rotten that the material came up as a mud, raises a very dif-
ficult question as to the conditions that make such extensive
decay possible.

Hole 7 (113th street) shows extreme decay to Elevation
-204 feet.

Hole 16 (110th street) shows similar condition to Elevation
-250 feet.

Hole 36 (108th street) show r s similar condition to Elevation
-185 feet.

These three holes showing similar condition of very deep
decay are located almost exactly in line. Nothing on either
side of this line is in so poor condition.

Consideration of these conditions can not fail to raise cer-
tain questions of interpretation.

(1) It would appear that at least one of these borings
(No. 7) is near the schist-limestone contact. May they all lie
then in the weakened contact zone?

164

(2) It is true that at least one core (also from No. 7) shows
a badly broken condition. May they all lie in a fault zone ?

(3) There is no reasonable doubt but that the geologic
structure at the south end of Morningside park is that of a
pitching anticline carrying the limestone beneath the schist in
its southward extension. May the excessive decay be due to
this relation?

The evidence on these various possibilities is not complete
enough to make a conclusion very reliable. But there are two
or three factors that have a bearing and they unite reasonably
well in supporting one view.

These factors are: (a) the exact alinement of these three
holes, (b) the crushed core of Hole 7, (c) the overturned posi-
tion of the formations 10 blocks farther north (Hole 33), to-
gether with the apparently normal position in Hole 16.

All of these points are consistent with the opinion that we
have to do here with the crush zone of a fault, one that runs
straight and one that follows not far from the contact of the
schist and limestone at this point. And it is probable that the
weakness follows the west margin or limb of the limestone anti-
cline as it plunges beneath the schist. Such evidence as there is
favors this view.

If that is true, then one may expect that the w r orst ground
is not very wide, but that one probably can not go entirely
around it. The best line would run south far enough to get
above the limestone, and then cut across the weak zone, at right
angles, wholly within the schist formation. It is certain that
the ground improves southward.

Later borings are all confirmatory. of the conclusion that the
weakness is narrow and dies out rapidly southward as soon as
the limestone passed well beneath the schist. No bad ground
has yet been found on 106th street where the tunnel has been
located.

The line was finally located four blocks farther south on
106th street, because of the conditions just described, and a
number of borings were made between Columbus avenue and
Central park for the purpose of determining whether or not
the same weaknesses would be encountered there. All of the
borings show Manhattan schist to as great depth as they were
carried, and indicate rock of as good sound character as the

166

average on Manhattan island. With these results bearing out
the opinion based on the geologic relations, no difficulty is
anticipated at this point.

The East River Section

Preliminary studies of southern Manhattan and the East
river as already given, led originally to the conclusion that the
portion of the East river forming the great eastward bend
from 32nd street to Brooklyn bridge probably has a simpler
geologic structure than those portions farther north or south.
It was long known that the structure at Blackwell's island is
very complex and involves all of the local formations in close
folding and considerable faulting. After studying all avail-
able data, there seems to be good reason to believe that the
river leaves this belt when it bends to the eastward and that
it is in this part a displaced stream. In that case the East
river could be flowing upon a floor of gneiss of a most sub-
stantial sort.

Explorations are now complete on a line that crosses the
river from Clinton street, Manhattan, to Bridge street, Brook-
lyn. All borings have found good sound rock at moderate
depth and all are comparatively shallow holes. Their positions
and rock types are tabulated below :

Distances in

Elevation of

Number

Feet From

Approxi-

Rock Floor

of

Manhattan

mate

Below Mean

Type

Form-

Boring

Pier Head

Interval

Sea-level

of Rock

ation

Line

in Feet

in Feet

9

-48

Grano-diorite

Fordham

21

225

225

-65

« i

53

350

125

-72

4 t

32

525

175

-71

• *

50

695

170

-76

« •

34

860

165

-74

• »

41

960

100

-81

1 *

39

1,070

110

-87

4 •

67

Brooklyn side

4 4

near bulkhead

• • •

-75

Banded gneiss

ft •

The rock floor is thus very uniform as to contour across
the East river at this point. No water course yet explored
about Manhattan island has shown so simple conditions includ-
ing as it does sound rock and shallow channel. The rock varies
a. good deal but is prevailingly a coarse grained grano-diorite.

SHEET 11

3AV 3UMAH.

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>-

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+3 co « ^

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•d C0~* «

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o ti oo 5

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o

168

In places it is very garnet iferous and at others is banded or
micaceous, but all belong to the Fordham formation as a gen-
eral formational unit.

Borings in the East river made by the Public Service Com-
mission both above and below this point found an occasional
zone with excessive decay to more than a hundred feet without
securing sound core. At this crossing, selected for the distri-
bution conduit, the deepest point in the channel to sound rock
floor is only 81 feet.

It is certain from these results and from others in adjacent
ground that the East river in this part of its course does not
occupy the original stream channel. It has been displaced
(evicted) by glacial encroachment and has never been able to
reoccupy the lost course. Therefore, instead of the river fol-
lowing a belt of limestone around this big bend, as was formerly
supposed, it follows no rock floor structure at all but is in this
part of its course wholly superimposed. The original valley
lies farther to the west cutting through the midst of the lower
east side where more complicated geologic structures again
prevail.

Borings at intervals of 500 feet have now been made en the
Brooklyn side of the East river to Gold street and Myrtle ave-
nue. So far as developed there is no other formation than
the Fordham and the associated grano-diorite within the area
covered. The rock floor is remarkably uniform at an eleva-
tion of from -70 to -90 feet. The accompanying section
shows the relations of rock floor to present drift surface
(Sheet 11).

STRUCTURAL GEOLOGY OF THE LOWER EAST SIDE, DELANCEY AND

CLINTON STREET SECTION

The proposed distributary conduit turns from the Bowery
eastward on Delancey to Allen street, thence on Allen to Hester
street, thence on Hester street to Clinton street and follows
south on Clinton to the East river. This so-called Lower East
Side section includes one of the most complicated geologic
structures in New York City. The most complex portion ex-
tends from Chrystie street on the west side to Monroe street on
the east. Between these two points all of the crystalline rock
formations form a series of parallel beds that are folded to-
gether so closely that they stand practically on edge.

169

This general fact and the approximate location of the sev-
eral beds have been proven for some time. But the more exact
structure, with the depths to which the beds go before bend-
ing upward again, and the distances through each one are only
approximately determined by the exploratory borings. Ad-
ditional obscurities arise from the fact that the beds are also
faulted, the dips of the fault planes are not fully determined
and the amount of displacement is unknown. The difficulty
of forming a good estimate of such points is greatly increased
by the fact that no rock of any kind is to be seen at the surface.
Judgment is based wholly on borings.

There are other important questions touching this zone,
such as: (1) the depth of serious decay, (2) location and
width of these decay belts, (3) general physical condition of
the rock at certain levels, (4) length of tunnel that will cut
each formation, (5) best depth for safe construction.

The accompanying geologic cross-section (Sheets 12 to 15)
embodies an opinion of the structural relations of the different
formations. It is offered as an interpretation of borings to
date, and its more direct use is as a working basis and guide
in conducting explorations. The western half of the section
may be accepted as more accurate in minor detail than the
eastern.

To simplify the section it is drawn on a line crossing this
zone more directly than the conduit as laid out, i. e., through
Holes 28 and 5 and the borings are projected along the strike
of the formation to the section line. All the data therefore
are used and the structure is not distorted, but the distances
through each bed would be greater on the conduit line because
it runs more diagonally across the formations.

BORINGS

Many borings have been made on this section between the
Bowery and the East river. No other portion of the line has
required so elaborate exploratory investigation to satisfy the
demand for reliable data.

The drift cover lies very thick on a variable rock floor. The
maximum thickness indicated is 240 feet by Boring 219 at
the corner of Clinton and Madison streets. It is largely modi-
fied drift such as sand and gravel; but there is enough heavy

170

bouldery ground to give much trouble in sinking to bed-rock
with the drill.

Samples obtained by drilling have proven to be more varia-
ble and the data all together are more difficult to interpret than
at any other point. Many of the borings indicate considerable
rock decay to depths of 500 or even, in rare cases, to 600 feet.
In a large number there is evidence of crushing and movement
such as is commonly developed by faulting. In a large num-
ber there is abundant evidence of alternating layers of lime-
stone and gneiss together. In some of the holes more than one
limestone bed is penetrated. There is furthermore a great
variation in angle of dip in different places — sometimes even
in the same hole, but the average dip is certainly greater than
45 degrees.

Four important types of rock occur in the Lower East Side
section. Manhattan schist lies beneath the Bowery at Delancey
street and extends one block eastward to Chrystie street.
Inwood limestone then forms a belt a block and a half wide
between the schist and a strip of Fordham gneiss, which is only
about a block and a half wide also. A strong belt of limestone
lies immediately to the east, and this is followed by a remark-
able series of interbedded layers of limestone and gneiss belong-
ing to the Fordham gneiss series. This continues as far as
Monroe and Clinton streets, where there is a decided change
and thence southward to the East river and across it and into
Brooklyn the prevailing type of rock is Ravenswood grano-
diorite.

These four formations have the usual structural relation.
The schist, limestone and gneiss are clearly folded so that
their eroded edges form parallel belts striking about North
30° East. The Ravenswood grano-diorite is intrusive in the
Fordham gneiss.

FAULT ZONES

Fault movements have disturbed the strata also and those
of later time are not rehealed, but still show crush zone effects.
These are the weakest places in the rock floor and are the
places where rock decay extends to great depth. All of the
evidence thus far secured leads to the conclusion that these
zones of weak rock are all very narrow, that they strike
parallel to the strata, and that they become gradually but per-

171

manently more substantial with increase of depth. Doubtless
there is a tendency for decay effects to follow some of the
weaker beds of rock across which the faults cut, and in this
way one finds some decay of rock in undisturbed material at
surprising depths. But this effect is undoubtedly very local
and always closely associated with adjacent crush zones which
have been the real sources of the attack.

It is clear that the limestone belt at Forsyth street is too
narrow to accommodate the whole normal thickness of In wood,
750 feet. It is therefore certain that a part of it has been
cut out by faulting or it has been squeezed out in the fold-
ing process or else it is not the same formation at all. The con-
dition of the rock at the contact between limestone and gneiss
shown in Boring 223 supports the view that there is faulting
along this contact.

INTERBEDDED LIMESTONES IN THE FORDHAM SERIES

Numerous narrow limestones are interbedded with the
quartzitic and schistose layers of the Fordham gneiss series.
Nowhere are they more abundant or more persistent than in
the Lower East Side section. All of the borings within the
gneiss area of this district except those near the East river
have shown some limestone.

Individual beds vary greatly in thickness. Because of the
steepness of dip, and the obscurity of this factor in many cases,
it is not possible to compute them closely. It is probable that
most of them are not over 5 to 10 feet thick, although rarely
a thickness of 25 or 30 feet may be represented. It is certain
also that a considerable number of separate beds are pene-
trated. All attempts to correlate the limestone cores from
different adjacent holes have so far met with little success.
No doubt some of those cut at great depth in one hole cor-
respond to others cut higher in an adjacent hole. But the dif-
ferences in thickness are notable even in the best cases, and it
is evident that little dependence can be put upon uniformity
of thickness as a factor in correlation. The foldings and
crumplings and shearing have probably affected the limestone
members of the series more than any others. Limestones in
comparatively thin beds are, under such conditions, especially
liable to excessive thinning and thickening through recrystalliz-

172

ation and rock flowage. It is therefore not at all likely that
any single bed at present preserves much uniformity of thick-
ness. In some places they are pinched out entirely while in
others they may attain a thickness much greater than the
original. It is possible also that some of them are repeated
by folding. Whether or not this is true in the Lower East
Side section has not yet been determined. On the whole there
is no direct evidence of repetition in this way. After making
allowance for all possible duplication there is still a surpris-
ingly large number of limestone interbeds represented — prob-
ably 10 — a larger number in succession than is known any-
where else in southeastern New York (see Sheets 12 to 15).

In petrographic character these so-called limestones are all
essentially very coarsely crystalline dolomitic marbles or sili-
cated dolomites of still more complex constitution. Occasionally
a very pure carbonate rock is represented that corresponds
in appearance very closely indeed to the best grades of the
In wood, but there is no doubt whatever of the true inter-
bedded relation of these limestones. Their similarity of appear-
ance to the Inwood in certain facies is so great that from the
petrographic evidence alone one could not differentiate them.
Their field relation, however, is unmistakable and they belong
unquestionably to an entirely different geologic formation from
the Inwood — a much older one, in fact the oldest known forma-
tion in southeastern New York — equivalent to the Grenville
series of the Adirondacks and Canada. The silicated facies
contains many of the common products of metamorphic pro-
cesses. Recrystallization has produced micaceous minerals
such as phlogopite and chlorite in abundance. Original and
secondary quartz is plentiful. Serpentine, tremolite, diopside,
actinolite, occasionally chondrodite, and rarely metallic ores
are found. In many cases the limestone passes by transition
gradually into a more and more siliceous facies until the rock
is simply a siliceous Fordham gneiss with quartz, mica and
feldspar as the essential constituents. There is seldom a sharp
break between the two types. Many pieces of apparently sim-
ple gneiss will show effervescence or a carbonate constituent
with acid.

The siliceous beds of the gneiss series proper immediately
associated with the limestone layers are also more siliceous or

173

more micaceous than the average Fordham. They are essen-
tially micaceous quartzites and mica schists and the rock
generally lacks the strong black and white banding that char-
acterizes the common or typical Fordham gneiss of other local-
ities. It is this facies of the gneiss which most closely resembles
certain varieties of the Manhattan schist, and when the rock is
much decayed or badly broken or is ground to pieces by the
drill the confusion is still greater. The micaceous variety
may readily be mistaken for Manhattan schist and the accom-
panying limestone may equally be mistaken for Inwood.

The occurrence of interbedded limestones in the Fordham
series is probably more common than was formerly believed.
They are not very often seen on the surface in areas of gneiss.
Possibly this is largely due to differential weathering and
erosion which together tend to obscure those portions of out-
crops where such beds may occur. But the type is well known.
It is certain that there are interbedded limestones with the
gneisses in the Highlands. There are similar occurrences in
the typical Fordham gneisses of The Bronx, New York City.
The vicinity of Jerome Park reservoir is the best locality in
all southeastern New York to see this interbedded develop-
ment. The best exposures are at the following places :

(1) In the margin of Jerome Park reservoir at 205th
street.

(2) East side of Villa avenue north of Bedford Park
boulevard.

(3) East of the Concourse between 198th and 199th
streets.

(4) South side of 196th street both east and west of the
Concourse.

These occurrences in the vicinity of Jerome Park reservoir
are essentially the same as those disclosed by the borings of
the lower east side. In spite of its thick drift cover — 50 to
200 feet — there are more limestone interbeds known there than
in any other area of similar size in the region. It is entirely
possible that a thorough exploration in certain other belts
might reveal an equally elaborate development elsewhere.

The finding of interbedded limestones as a prominent ele-
ment in certain facies of the gneiss series and their association
with typical siliceous gneiss layers with transitional relation

174

emphasizes still more the strictly sedimentary origin of at least
some portions of the Fordham series. Other observations lead
to the conclusion that they are the oldest members of the series
and that the igneous associates, of which there are many, are
all younger intrusives.

One of these later intrusives is the Ravenswood grano-
diorite which cuts into the eastern margin of the lower east
side, forms the floor of the present East River channel at the
point of aqueduct crossing and continues as far as explora-
tions have been carried into Brooklyn.

All of these factors and as much of the detail as seems
useful are included in the accompanying cross-section (Sheets
12 to 15).

CHARACTER OF THE DRIFT COVER OF THE
. LOWER EAST SIDE SECTION AND ESPECIALLY
THE DELANCEY STREET SHAFT SITE

Boring 225 on Delancey street between Eldridge and Allen
streets is a proposed shaft site. Many other borings have been
made in the vicinity — on Delancey, Grand, Hester, and Clinton
streets — most of which also have given reliable evidence as
to the character of the drift above the rock floor.

The following is a tabulation of the materials representing
the drift cover at Boring 225.

Elevation of surface — about 40 feet.

Depth of drift cover above rock floor — about 114 feet.

Water-table about 30 feet below the surface.

Detail of materials:
feet to 10 feet — medium sand rather uniform.
10 feet to 20 feet — coarse sand of mixed character not so

well assorted.
20 feet to 30 feet — coarse sand and fine gravel — mixed char-
acter but washed clean.
30 feet to 40 feet — same.
40 feet to 50 feet — medium sand — clean.
50 feet to 60 feet — fine sand — much finer than above.
60 feet to 70 feet — very fine sand or silt.
70 feet to 80 feet— fine sand like that from 50 feet to 60 feet,

but not so fine as the last number.
80 feet to 92 feet — verv fine sand like 60 feet to 70 feet —

packs down well — reddish color.

r

~/oo

-200
-300

-400
-500

-000 -
-TOO

\

***.
&

fa

T3T

4

*2 /?/*
+5 f7#e

»* i

B.W.8. 652

II . ~

' * «

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7

■• ■ *

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I

■

t

I

' »* » r

w i,

v

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.. I

*\ • v. *. V-

■ ^-4 v **

, ► N » '* > . ».» >V » "'* "'

. ') -' //

*• l» 1« I

* «, #.*

SHEET 14

#2 /7/7e
I #3 Cocrrse &r/?af

?4- S/eef/i/m - -

f£ /7/re " **

*6 S&fier/foe ** -

*7 ffocAf/ovr^cr/qy "

S Scwcf

G Grare/ -

B.W.S. 678 G* 7 *"** wfer e/eya//0/7 rar/es Ttv/r? O/b +7

*9

S+r / mm.

/ n .5 mm.

J> » £5 mm.
25 - JOm/n.
J? » .05 /??m.
£5 - £>/ ma.

City of New York
BOARD OF WATER SUPPLY

CATSKILL AQUEDUCT

CITY TUNNEL

BORING RECORD

100

200 Ft

DECEMBER 15., 19K>

Revised to Jan 31* 1912

SHEET 15

'*/ Coarse tfrerre/
&3 Cocrrsie &v?cf

*5 f7#e

*6 Scperfwe '•

*7 ffoc/cf/ovr«*rCYarr

Grzx/Mt wafer e/eyaf/0/7 rar/'es
frvm 0ft>+7

B,W.S. 653 Revised to Jan 31* I9l2. k

S 777/77.

/ mm-
.5 mm.

J25 777/77.

JO m/77.

.05/77/77.
JO/ /77/T7.

City of New York
BOARD OF WATER SUPPLY

CATSKILL AQUEDUCT

CITY TUNNEL

BORING RECORD

100

100

200 Ft

■BO* '

DECEMBER 15, 10K)

■■HI

.

177

92 feet to 104 feet — very fine sand — nicely assorted and uni-
form — dark bluish gray color.

112 feet to 114 feet — coarse sand and fine gravel — mixed

character and very variable.

Comment

Nearly all of these materials are assorted sands and gravels
and doubtless represent strongly stratified drift deposits. An
analysis of the record of the hole shows that the coarser sands,
some of which carry an abundance of fine gravels occupy the
upper 40 feet and a thin layer of a few feet near the bottom^
Very fine sand (silt) is the prevailing quality from a depth of
50 feet to 104 feet.

Fine sands of so uniform grade mean that at this depth
they are unusually well assorted and were probably laid down
in standing water or rather quiet water into which these mate-
rials were carried as a silt. There is every reason to believe
that they are horizontally stratified and that similar character
of deposits prevails throughout the vicinity.

Some of the samples have the appearance of " quicksand."
There are doubtless some portions of this zone between 50 and
104 feet that will behave like a quicksand in working.

The general freedom from fine mud and the very clean
character of all of the samples indicates that there is prac-
tically no " till " or boulder clav and that the whole drift
cover is very pervious to water. It is certain that these sands
are saturated with water, that they hold great quantities of it
wherever the assorted drift extends and that there is easy
underground circulation which is no doubt more free laterally
than vertically.

Other borings in this district, although they vary considera-
bly among themselves, show similar character of materials.
They support the conclusion that porous stratified fine and
coarse sands and gravel underlie all of that portion of the lower
east side which has very deep rock floor.

Application

The Delancey Street shaft will penetrate very troublesome
ground throughout most of the 114 feet of stratified drift that
covers the rock floor.

178

The lower 50 feet may be expected to exhibit quicksand
behavior.

The whole shaft below the water-table (30 feet) to bed-
rock (114 feet) will be exceedingly wet. There is no doubt
about the abundance of water. This together with the caving
tendencies of such fine-grained water-logged sands will make
it necessary to adopt special measures for handling the ground.

It does not appear that any other site in the immediate
vicinity would give materially different conditions.

GEOLOGICAL CONDITIONS AT THE PROPOSED

SILVER LAKE RESERVOIR

Silver lake in the northern part of Staten Island has an
elevation of about 200 feet above the sea. It occupies the
upper portion of a small valley opening southward, and is
separated on the north by a low divide from another depres-
sion which opens westward. It is proposed to utilize both
depressions as a reservoir site, keeping the two basins separate
by a dike. Catskill water will be led to this point from the ter-
minal shaft of the distribution tunnel in Brooklyn through steel
pipes and a short approach tunnel.

Questions

Questions of immediate consequence bear chiefly upon the
geological character of the locality.

(a) What are the geologic formations?

(b) Are the basins essentially impervious or will they re-
quire lining?

(c) Is there good material for dike construction on the
ground ?

Geological Formations

The rock floor is entirely covered with glacial drift in the
immediate vicinity of the Silver Lake site. But on all sides at
no very great distance the character of bed-rock is known.

There are only two formations: (a) The Staten Island
serpentine, and (b) Glacial drift.

The Staten Island serpentine occupies almost the whole of
the elevated portion of Staten Island. Within the area in
which it is known to occur, no other rock formation has ever

180

been found. This formation is unlike anything yet encoun-
tered on the Catskill Aqueduct work. The serpentine is more
closely related to the old crystalline schists and gneisses,
known as Manhattan schist and Fordham gneiss, than to any
others, but it is an independent unit. This rock was originally
an igneous intrusive of very basic composition (probably a
pyroxenite) which pushed or fused its way into tke old crys-
talline schists and finally cooled as a great mass or ** boss."
It is thus of the same origin and form as the granite masses
encountered at several places in the Highlands, or the grano-
diorite of the East River district.

But this old basic rock has yielded much more readily to
alteration and modification than the more acid granite types
and as a result common greenish hydrous magnesian silicates
as secondary minerals are developed in such abundance that
the whole rock is called " serpentine." In most cases not a
single original mineral constituent can be found, but traces of
original structure can be seen microscopically, showing with-
out doubt that this is the origin of the rock. The serpentine
mass extends downward indefinitely. It is essentially a massive
rock — lacking all banding or bedding or marked foliation. It
is much jointed — very irregularly, but the joints are fairly
tight.

The glacial drift cover is everywhere on the surface a heavy
bouldery till. It varies greatly in thickness from only four
to five feet to perhaps 100 feet. Xo one can tell from surface
appearance just how thick it is, but exploratory borings show
that depressions are much more heavily covered than the hill-
sides. It is nearly all of the mixed drift ("till") type —
boulders, gravel, sand, and clay all mixed together.

Imperviousxess of the Bastns

The existence of serpentine as the bed-rock formation has
been proven at all points as was to be expected. No unlooked
for or unusual conditions or structures have been discovered
or indicated in this rock. It is essentially massive and much
jointed, but the crevices do not stand open conspicuously.
These crevices form a complex network of possible channels
for ground-water, but the amount that the rock as a whole
can carry and the extent to which circulation is encouraged

181

by this condition is certainly comparatively small. There is no
such thing as interstitial porosity like in a sandstone, or bed-
ding structure like in sedimentary rock. Such water as may
find its way out of the basin through the surrounding and
underlying bed-rock must follow the most tortuous courses,
its movement must be extremely slow, and its effect on the
rock itself is practically nil.

Bed-rock of the type of the Staten Island serpentine may
therefore be regarded as practically impervious. This rock cer-
tainly forms the enclosing wall on the east side arid north side
complete and for most of the distance on the west side No
better bed-rock exists in southern New York for such purpose.

But probably at no point will the waters of this reservoir
come in direct contact with the bed-rock. Everywhere there is
an overlying mantle of glacial drift, soil, and lake mud, which
has a more direct bearing on the question of efficiency in hold-
ing water than the bed-rock itself. This is because the drift is
deep at the very places where the natural tendency of water
flow is greatest, i. e., in the valley bottoms toward the south
and toward the* we'st; and, if pervious enough, it would be
possible to lose all of the water of both basins through this
material, no matter how impervious the bed-rock may be or
how perfect a dike were built on top of the drift.

The most essential thing then is the character of the drift
at these critical points — the places to be occupied by the South
dike, the North dike, and the West dike. These conditions
have been discussed in detail in special reports. It is fair to
say at this point that there are yet at each point some minor
explorations to be made. But data have been accumulated of a
decidedly reliable nature bearing on this question, and, assum-
ing that the additional exploratory work reveals similar con-
ditions, it seems to me that there will be no doubt about the
water-holding efficiency of the whole reservoir. The type of
drift mantle is prevailingly a heavy bouldery or stony till with
only here and there patches or lenses of pervious sands and
gravels of very limited extent which appear to be so interlocked
with the impervious material that the whole mass, when treated
on a large scale, becomes essentially as impervious as a " till."
This result is decidedly encouraged by the fact that there is
almost everywhere a layer of dense impervious " till " on top

182

so that the tendency to start circulation in the drift is checked
at its beginning. Furthermore, where the 3 dikes are to be
placed, which cover at the same time the only critical spots,
there is in each case a wide stretch of ground, both in front of
and behind the dike, in which the same general type of drift
occurs, adding materially to the obstruction of water circula-
tion.

It is as tight and impervious as the average " hard-pan " or
till of southern New York. There is every reason to regard this
material as an eminently satisfactory natural lining of the
basins as they now stand. It is also suitable for use as dike
material. The fact that Silver lake holds water permanently
in all kinds of seasons is sufficient proof of the efficiency of this
natural material. The basins will not require lining.

Material for Dike Construction

An abundance of mixed drift (" till ") is available for such
work. It is probable that some places are more clayey than
others and therefore better suited to such use. In all cases
material in the immediate vicinity of the Work is suitable for
its construction. No better is likely to be obtained on the island.

Explorations

Borings into bed-rock have shown low core saving and in
places a poor quality of rock. The serpentine as a whole is
rather soft and much jointed and is easily ground up in the
drilling process. But in this it does not differ from the rock as
seen elsewhere in the vicinity.

Exploratory borings have been made on the sites of the
proposed dikes and the data have been interpreted and plotted.
The accompanying structural profiles (see Sheet 17) exhibit
items furnished by this investigation that have a bearing
on the questions under present discussion. It is evident
at once, from an inspection of the borings, that the rock
floor lies as much as 99 feet below the surface at the deepest
notch where the south dike cuts across the outlet. But an
interpretation of the samples saved during the progress of
the work leads to the conclusion that the drift material as
a whole is tight and of fairly good quality for the uses intended.

This diagram, showing the profile and borings data, is like-

SHEET 17

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City of New York

BOARD OF*WATER SUPPLY

SILVER LAKE RESERVOIR BORINGS

ILES PERPENDICULAR TO THE SOUTH DIKE

40

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60 Ft.

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JULY 30,1912.

Acc.C5337

V

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183

wise an illustration of the most satisfactory method of taking
and recording samples. It covers only the explorations on two
lines crossing the site of the South dike, but this is typical local
ground, and the drawing tabulates the most important items of
geologic interpretation of the borings so fully that it may well
take the place' of a more extended discussion.

Summary

(a) There are only two formations to be considered at this
reservoir site — The Staten Island serpentine and the glacial
drift.

(b) The two basins are essentially impervious — both form-
ations favoring this condition.

(c) Suitable material for dike construction is available on
the immediate ground.

(d) Exploratory borings show reasonably good type of
drift even to the deepest portions of the dike sites.

The geologic features on the whole are very favorable,
and there seems to be every reason to expect additional ex-
plorations to further support this opinion.

ON THE QUESTION OF FEASIBILITY OF THE TUN-
NEL PLAN

Additional exploratory investigations have been made at
some of the shaft sites and at the north end of Morningside
park since the original reports, on which the above discussion
is based, were written. Explorations were continued on the
lower east side up to the time of the beginning of actual con-
struction. Although considerable additional detail accumulated
from these sources, there were no new features discovered
and no new or unlooked for conditions disclosed of sufficient
prominence to modify the descriptions and opinions, already
formulated, further than to determine the extent and boun-
daries more closely.

The Lower East Side section has claimed special attention
from the beginning and this is still kept up. Exploratory work
is slow and much hampered by heavy drift cover. This fact,
together with the difficulty of interpreting some of the mate-
rials secured from boring, led to a fairly general belief that
the ground itself is especially poor for tunnel purposes. A

184

thorough study of all of the data, interpreted in a manner con-
sistent with the known geologic characteristics and habit of
the region, does not support such a view. Neither exploration
nor construction, so far as it has progressed, have shown any
condition that can be regarded as sufficiently questionable to
make the tunnel plan of distribution conduit impracticable.
On this point the opinion written March 22, 1910, the essential
parts of which are given below, either in quotation or abstract,
needs no revision.

The most important question involved in the outcome of
these explorations is whether or not the bed-rock tunnel is
feasible. Or are there known conditions which cannot be
avoided that would make such construction unsafe or insecure?
Or are the unknown portions or untested stretches of enough
uncertainty to throw a reasonable doubt on the practicability
of the enterprise?

Even preliminary studies and explorations show beyond
question that nearly the whole line could be located within
formations of constant character and known quality about the
behavior of which there is no reasonable doubt. Only at a few
places has it been advisable to pursue exploratory work in
much detail. These places are:

(a) The Harlem river (167th street).

(b) Manhattanville cross valley (125th street).

(c) Morningside to Central park (106th and 110th streets).

(d) Lower east side (the Bowery and East river).

(e) East River crossing (Clinton street to Bridge street).
Whatever uncertainty or question there can be about the

practicability of the tunnel plan must arise in connection with
some of these points, all of which have been extensively ex-
plored.

At the Harlem river the geological conditions on the pro-
posed line are proven to be essentially identical with those 2,000
feet further north where the New Croton tunnel is located.
The crossing is therefore understood and, as already shown by
this Croton tunnel, the rock tunnel plan is clearly practicable.

At the Manhattanville cross valley, between 123rd street
and 127th street, thorough explorations show that Manhattan
schist of normal type is continuous and that there is no very
deep decay. The rock is of a type and quality that is well
known in this City as suitable for large tunnels.

185

From Morningside to Central park the line finally
selected extends southward on Columbus avenue to 106th
street and thence eastward to Central park. Explorations
show that a good grade of Manhattan schist exists wherever
tested on this line. The borings were located at places judged
to be most likely to show poor ground, but the results indicate
that the weak ground has been avoided. No local conditions
are known that throw any doubt on the feasibility of this por-
tion of the line.

On the lower east side, on Delancey, Hester and Clinton
streets, all of the local formations are crossed in a series of
narrow belts that exhibit complicated structure. Proper inter-
pretation of all data leads to the conclusion that the belt is of
essentially the character and relation that one can find else-
where and that was to be expected in some form here. There-
fore it is understandable and the chief object of exploratory
investigation has been accomplished. There are no new prin-
ciples involved and no new conditions. The only feature di-
rectly affecting the question of practicability is that of depth
of decay, and, as a consequence, the depth at which the tunnel
should be placed.

This is shown now to be deeper than at any other place on
the line, but it follows certain zones or belts that are com-
paratively narrow and that steadily become narrower and bet-
ter with depth until finally, in all cases, good, firm rock is
reached. There is no doubt whatever but that by far the
greater portion of the line across this belt passes through per-
fectly good sound rock even at moderate depths. By placing
the tunnel deeper, as has been done, the proportion of sound
rock is increased so materially that the possible amount of
weak ground becomes of little consequence as affecting the
whole scheme.

At the East river, explorations have shown that the rock
is in exceptionally good condition.

In summary, therefore, on the question of practicability
the following opinion maybe given.

The rock formations that will have to be penetrated all be-
long to well-known types in which tunneling is already ex-
tensively and successfully carried on. The only sources of
difficulty are connected with special local rock conditions where

186

there is crushing and decay. These conditions characterize
certain zones of determinable field relations — chiefly faults and
contacts. Sometimes such zones can be avoided by locating
to one side parallel to them. This is the method used in long
stretches where the original trial lines were shifted. If such
zones Have to be crossed there are still two ways of avoiding
the chief dangers of them. One takes advantage of the fact
that all structures tend to die out sooner or later along the strike
and therefore it is sometimes possible to go around the end out
of reach of the worst effects. This is the way adopted in
passing from Morningside to Central park accomplished by
shifting the line from 110th to 106th streets. The other way
is to go deep enough with the tunnel to get below the worst
effects of decay. This is the only way possible where a series
of persistent weak zones have to be crossed, and it is neces-
sarily the method employed through the lower east side.

A review of all data and consideration of th established
geologic characteristics of the locality, after making allowances
for every factor that can by any possibility modify present
evidence, has convinced those who have faced this responsi-
bility that the tunnel plan of conduit construction is entirely
feasible throughout the whole distance from Hill View reser-
voir to Brooklyn.

Yours very truly,

CHARLES P. BERKEY,

Geologist.

*m

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f

INDEX

PAGE

Affidavits 54, 113

Appendix

A 74-83

B 84, 85

C 86-89

D 90-93

E 94, 95

F 9-6, 97

G . ...' 98,99

H 100

I 101, 102

Bates, Lindon, Jr 5, 31, 35, 40, 91

Bensel, John A 48

Berkey, Charles P ,. 13

Berkey, Charles P., report on geology along City Tunnel line 115-186

Board of Estimate and Apportionment

advisers appointed by ; 31

approval of pressure tunnel plan 6, 7, 43

pressure tunnel plan submitted to 5, 29

report of advisers to 6, 60-73

report of committee to 7, 35-42, 103-106

resolutions adopted by 7, 43, 44, 57-59, 107

Borings 6i

results 84, 85, 87, 88

Brooklyn pumping-stations, advantages to 67

Brush, William W 23, 37, 39

Catskill water

availability 12

conditions governing delivery 11

consumption in Manhattan 67

plan for delivery to the boroughs 3, 4

advantages 27

approval of plan by Board of Estimate and Apportionment 3

approval of plan by State Water Supply Commission 3, 109-113

petition for approval by State Water Supply Commission 45-54

Chadwick, Charles N 47

Cincinnati tunnel £4

City tunnel

history of steps and stages 3-8

preliminary proceedings 3-8

report on geology along, by Charles P. Berkey 115-186

Clove Lake reservoir, capacity 21

Conduit lines, location .- 12, 74

Conduit system 9-11

cost of construction 11

Conduits

size ; 14

type 14, 15

capacity 15

construction cost per foot 15

determining factors of 14

suitable for various boroughs 19

II INDEX

PAGE

Consumption, water

Bronx, Queens and Richmond 12

Manhattan and Brooklyn 12, 67

Contracts for City tunnel

advertised 8

advertisements for, recalled 8

bids opened 8

Controlling sections of tunnels for City aqueducts 99

Cores, rock

microscopic examination of 88, 89

Cross-connection

between Manhattan and Brooklyn 11, 67

Delivery system 3, 4

cost 8, 22

length 8

pipe-line 23

time for construction . 21

tunnel and pipe-line 22

de Varona, I. M.

letter favoring pressure tunnel 32

Distribution system

effect of proposed, on system for Brooklyn and Richmond 18, 33

estimated cost 8, 18

Drill holes, details of 87, 88

Exploration of rock 81

Fordham gneiss 74, 76, 86

Fteley, A 63, 68

Geological conclusions 62

Geological data available 61

Geological formations found along line of tunnel 74

Geology

Lower East side, with reference to deep tunnelling 86-89

tunnel line 13, 74-83

report on, along City Tunnel line, by Charles P. Berkey 115-186

Harlem River crossing tunnel 63

Herschel, Clemens 73

Introduction 1

Inwood limestone 74, 76, 86

Kemp, James F . 13

Kern River hydro-electric plant, tunnel 64

Letters favoring pressure tunnel

de Varona, I. M 32

Spear, W. E 33, 34

Manhattan schist 74, 76, 86

Modification of map, plan and profile dated October 9, 1905 25-27

New York State Water Supply Commission

petition of the City of New York 6, 45-54, 109-112

petition approved 7, 109-112

petition granted 7, 109-112

New York subway

shaft progress 98

Parsons, William B 42

Pennsylvania crosstown tunnel 98

Pipe galleries 71

Pipe-line system 3, 4, 23

cost, estimated 11, 23

length 23

size 23

INDEX III

PAGE

Pipe line, 500,000,000 gallons capacity 94, 95

cost 94, 95

length 95

size 95

time for completion 94

Pipe line, 250,000,000 gallons capacity 101, 102

cost 101

length 101

time for completion 101

size » 101

Pipe lines

estimated cost in report of 1905 18

first cost comparisons with pressure tunnel 68, 69

48-inch cast-iron, cost per linear foot 97

66-inch steel, cost per linear foot 97

Pipes, metal 68

objections to ; 68

parallel mains, objectionable 68

Pressure tunnel

advantages 4, 5, 9, 15, 16

capacity 15

comparative projects 65

construction, time required for 21

cost estimate 70, 96

cost per foot 15

dangers due to rock condition 76-80

definition of 60

depth below street surface 8, 60

economic size j- - • 16-18

economy of, over pipe lines . . ...*.». 15

estimated cost of shaft sinking 96

estimated prices per linear foot 96

first cost comparisons with pipe-line 68, 69

geology 13, 74-83, 86-89

increased pressure 65, 66

location 17

location with reference to rock formation 80, 81, 88, 89

practicability 13, 60

routes, compared 69, 82, 83, 104-106

system 3, 4, 9-11

time of completion, estimated 71, 98

work to be done 8

Pressure tunnel, 500,000,000 gallons capacity 90-93

cost estimate 93, 100

length 92, 93, 100

pressure available 92

size 92, 93, 100

time for construction 93

Pressure tunnel, 250,000,000 gallons capacity

cost 100

length 100

plans 71

size 100

Pressure tunnel line

borings 84, 85

geology 13, 74, 83, 86-89

Pressure tunnel plan

advisers' report 6, 60—73

affidavits 54, 113

approval by State Water Supply Commission 7, 109-112

IV INDEX

PAGE

committee appointed by Board of Estimate and Apportionment 5, 31

majority report ......... .35-40

minority report •. •. 41, 42

report of 7-, 103-106

dangers in constructing and maintaining 76

delivery of 500 million gallons daily . 90

letters to Chief Engineer favoring • 32-34

petition to State Water Supply Commission 6, 45-54, 109-112

petition granted 7, 109-112

plan approved by Board of Estimate and Apportionment 6, 7, 43, 44

plan submitted to Board of Estimate and Apportionment 5, 29

public hearing 5, 30, 55, 56

recommended by Chief Engineer 5, 25-27

report on, by Wm. W. Brush ; 9-23

resolutions adopted by Board of Estimate and Apportionment 7, 43,

■ 44, 57-59, 107, 108

Pressure tunnels in the United States 62-64

Pressure tunnel under City of Washington . 63

Pressure tunnel under the Harlem River 63

Progress

shaft excavation 98

tunnel excavation 98

Pruyn, Francis L 73

Public hearing on pressure tunnel plan 5, 30, 55

Pumping dispensed with 66

Pumping, estimated cost of 66

Regulation of water pressure 66

Reports

advisers' 6, 60-73

Board of Estimate and Apportionment 7, 35-42, 103-106

Brush, W. W : . ... . . 9-23

Reservoirs

Clove lake, capacity 21

equalizing 20

in Richmond, cost 93, 102

Silver lake, capacity 8,21

Silver Lake, cost 21

Resolutions

adopted by Board of Estimate and Apportionment. . 7, 43, 44, 57-59, 107, 108

Rock along tunnel line 74-76

Rock borings, results of 84

Rock condition, damages due to 76-80

caving of material 77, 78

inflow of water. 77

leakage 77

Rock, exploration 81

Rocks encountered in tunnelling, proportion of 76

Sewer tunnel, Yonkers 98

Shaft progress

Moodna 98

New York subway 98

Rondout 98

Wallkill 98

Shaw, Charles A 47

Silver Lake reservoir

capacity 8, 21

cost 21

Simmons, J. Edward 47

Spear, Walter E.

letter favoring pressure tunnel 33

INDEX V

PAGE

State Water Supply Commission 6, 7, 45-54, 109-112

Tunnel and pipe-line system 9, 10, 22

comparative cost 65

cost, estimated 11, 22, 93

length 22, 92, 93

size 22, 92, 93

Tunnel progress

Pennsylvania crosstown 98

Rondout 98

Wallkill 98

Yonkers sewer 98

Tunnels for City aqueducts

time for completion of critical shafts 99

Water consumption

Bronx, Queens, Richmond 12

Manhattan and Brooklyn 12

Water pressure, regulation of 66

Water supply

amount required for each borough 19

Water waste prevention 72

Woodman, J. Edmund 73

Yonkers gneiss 74, 76

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